The development of traditional maritime history is based on a reflection on the civilization view centered on land. Looking at the development of global ocean history, whether it is the Mediterranean history, Atlantic history, Pacific history in the European and American academic circles, or the maritime Asia theory in the Japanese academic circles, or the maritime transportation history and maritime history in China, at the beginning of its development, ocean history attempted to break through the land center in historical research, using the coast as the starting point of communication rather than the end point of civilization. Under this premise, the ocean is considered as an extension of two-dimensional space with openness and communication. Shipping, trade, openness, and communication, which are based on ocean navigation, have naturally become the main topics of ocean history, and even the imagination of ocean civilization. However, in recent years, there has been a vertical shift in the study of ocean history. The international academic community is increasingly inclined to replace the ocean as a navigation space with the ocean as a water body, and to rethink the research scope of ocean history. This has made the study of ocean history more three-dimensional, with rapid development in ocean history research from the air, seawater to the seabed. From the perspective of oceanic history in the air, ocean meteorology has become a hot topic. Braudel once regarded the climate of the Mediterranean as a relatively independent entity, emphasizing the influence of air currents from two directions on the Mediterranean climate. He believed that this stable meteorological structure had a decisive impact on the development of Mediterranean civilization. The new research on the history of ocean meteorology pays more attention to the instability of ocean meteorology, such as the unpredictability of hurricanes in historical periods and the mutual influence between human activities and ocean meteorology. Ocean meteorology is no longer considered a structured and unchanging constant, but an unstable variable. In addition to the oceanic history in the air, vertical connections below sea level are also receiving increasing attention. From the history of fisheries to animal history, from water bodies to the seabed, different living organisms such as plants, microorganisms, and non living organisms such as sea salt and seabed minerals have also entered the historical narrative. The ocean is not just a blue area on a map, but a three-dimensional space rich in content. David Armitage, a professor of history at Harvard University, proposed the theory of underwater history and advocated for people to pay attention to the history below sea level. Tamara Fernando, assistant professor at Stony Brook University in New York, and Norwegian historian Sher Eriksson have demonstrated the possibility of writing a history of the ocean through empirical research on oyster and pearl industries in the Indian Ocean and Pacific Ocean, respectively. In 2017, David Armitage, Australian historian Alison Bashford, and Sri Lankan historian Sugit Sivachindaram also launched a new book series on ocean history at Cambridge University Press, emphasizing the difference between the ocean as a water body and the ocean as a shipping space. The expansion from horizontal to vertical space has enriched and diversified the methods and objects of marine history research, presenting characteristics of locality, diversity, and complexity. Researchers have begun to pay more attention to in-depth studies of small ocean spaces, such as a small bay, a unique marine ecosystem, a delta at a river mouth, or a coral reef, all of which have their own unique histories. This kind of microscopic research is different from the traditional approach of using a sea as a channel for communication between surrounding land, which believes that the ocean has its own history; This transformation also echoes the micro and local shift in global history, promoting the development of ocean history research towards a more profound and critical spirit of reflection. The deeper difference between the two types of ocean history mentioned above, apart from their research perspectives and focus, is that the former mainly focuses on the significance of the ocean for human cultural exchange, while the latter studies the ocean as a natural whole. However, this research method that opposes nature and culture has been questioned in fields such as environmental history, as it is difficult to distinguish between nature and culture, and the ocean has dual attributes of nature and humanity. Based on this, the author attempts to propose the construction of a three-dimensional study of ocean history, advocating for a dialogue between traditional ocean history and emerging ocean history research. The three-dimensional study of ocean history can help integrate the vertical and horizontal aspects, and write a history of the integration of humans and nature, which mainly includes the following aspects. One is the three-dimensional transformation of ocean space. Examining the history of the ocean from a three-dimensional perspective rather than a two-dimensional one can help us uncover many people, objects, and environments that have been hidden in the two-dimensional ocean space. Taking crop research as an example, traditional ocean history focuses on species exchange generated through the ocean as a medium, such as the "Columbus Exchange" and other land animal and plant exchanges across oceans. Stereoscopic ocean history research pays more attention to the history of marine crops, namely the exchange, transplantation, and domestication processes of animals and plants in the ocean. The second is three-dimensional communication across spaces. The ocean itself is a closely connected, continuously flowing, and interconnected whole from the atmosphere to the ocean floor. The historical changes of climate change, seawater acidification, population distribution changes, and underwater ecological changes in the ocean are not isolated, but interrelated. Attention should be paid to the interactive relationships in the three-dimensional space of the ocean, and the research object should be examined from this more systematic perspective. The third is interdisciplinary and three-dimensional communication. Building a three-dimensional study of ocean history requires comprehensive and three-dimensional cooperation between natural sciences and humanities and social sciences, breaking away from the binary opposition between nature and culture. At the beginning of the millennium, historians have already proposed this possibility. In 2005, an international conference on ocean history was held in Denmark titled "Ocean History: A Multidisciplinary Perspective on the History of Marine Organisms". The conference brings together marine science and marine humanities scholars to discuss the process and causes of changes in life forms in the global ocean. The 2010 American Historical Society Annual Meeting explicitly stated that the joint participation of scientists and historians in the history of the ocean would become an important direction for the development of historiography, and that the history of the ocean needed to incorporate knowledge of cosmology, geology, and oceanography. At the academic forum "Beyond Planes: Cubism in Marine History Research" jointly organized by the Institute of Oceanography and the Department of History at Peking University in April 2024, participants explicitly stated that only by jointly assisting and interweaving humanities and social sciences with natural sciences - rather than developing in parallel in their respective fields - can they complement each other's knowledge blind spots, provide new perspectives and inspiration. Writing a three-dimensional ocean history requires the integration of global and local historical research perspectives in methodology. The high mobility and cross domain nature of the ocean naturally give it global historical features. The three-dimensional ocean history emphasizes the locality of research, that is, selecting one or more focal points on the vertical and horizontal coordinates, conducting critical empirical research through archives, field and laboratory data. Through empirical case studies, we aim to reflect, test, and challenge universal theories by seeing the big picture from the small. The three-dimensional study of ocean history requires researchers to possess both global knowledge, local knowledge, and embodied cognition. Researchers need to actively switch perspectives and explore new research topics between different knowledge systems. For example, American historian Demuth uses the perspective of whales in "The Floating Coast" to immerse himself in the history of the ocean, expressing what the ocean is and what it means through the embodied cognition of whales. At the level of historical materials, the three-dimensional study of ocean history requires a thorough breaking of the boundaries between humanities, social sciences, and natural sciences, and the use of textual historical materials, multi species ethnography, and laboratory data as research materials. In this way, a large number of natural science research results will enter the field of ocean history research as new historical materials. At the same time, we also need the intervention of marine natural science knowledge to help us interpret these new historical materials. For example, currently, the trade route of cod in Europe can be determined through isotope determination, the transplantation path of kelp from Hokkaido to China can be traced through molecular genetics, and underwater archaeology can be conducted through deep-sea diving equipment to search for the remains of the Sino Japanese War of 1894-1895. In the future, methods such as foraminifera dating and climate simulation will help us understand climate change on a larger temporal and spatial scale, as well as the oceanic climate history in a planetary sense. In the joint research of natural sciences and humanities and social sciences, the history of the ocean will not be dissolved, marginalized, or weakened by the addition of natural sciences, but will gain stronger tools, more diverse historical materials, and more innovative methods. Building a three-dimensional study of ocean history also requires us to establish correct ocean values. In 2021, when the United Nations Decade of Ocean Science for Sustainable Development (2021-2030) was launched, humans had only completed mapping of 19% of the seabed, and still knew nothing about the distribution of species and ocean processes in the vast deep sea. What values should we uphold to explore this unknown world? We need to abandon the concept of anthropocentrism, care for the ocean like we do for life, continuously deepen our understanding of the ocean, attach importance to the construction of marine ecological civilization, protect marine biodiversity, and promote the achievement of sustainable development goals for the ocean. (New Society)