Recently, China has made significant breakthroughs in the field of optical lattice clock research. The strontium optical clock team led by Chang Hong, a researcher from the National Time Service Center of the Chinese Academy of Sciences, has successfully developed a strontium optical lattice clock whose frequency stability and system uncertainty are better than 2 × 10-18, which has improved the time accuracy to 16 billion years without a second difference. This achievement marks that China's development level in the field of optical lattice clocks has entered the world's leading ranks. To achieve this ultra-high precision, the team deeply integrates multiple cutting-edge technologies and innovatively combines mobile optical lattice technology, Faraday cage technology, active temperature controlled thermal screen cavity technology, and shallow optical lattice technology, effectively solving the problem of difficult to break through measurement accuracy of frequency shift terms such as blackbody radiation frequency shift and density frequency shift in traditional strontium optical clocks, reducing them to the level of 10-19, while controlling the DC Stark frequency shift at the level of 10-20 for a long time. The achievement has been published online in the authoritative academic journal "Metrology" in the field of international metrology. The reviewer believes that "the latest strontium optical clock developed by the National Time Service Center has achieved the second smallest uncertainty optical clock in the world." The strontium optical lattice clock developed this time fully meets the requirements for optical clock performance when the definition of the time unit "second" is changed in 2030, which was passed by the 27th International Conference on Weights and Measures in 2022. This makes China the second country after the United States to achieve optical lattice clock performance (frequency stability and system uncertainty) better than 2 × 10-18, further enhancing China's discourse power and influence in the international optical clock field. (New Society)