Laser interferometry measurement refers to a method of precise measurement using laser as the light source, laser wavelength or laser frequency as the reference, and the principle of light interference. It has the advantages of non-contact measurement, high sensitivity, and high accuracy. Laser interferometry measuring instruments are generally used for measuring displacement, length, angle, surface basis, and changes in refractive index of media. Commonly used interferometers include Michelson interferometer, Mach Zehnder interferometer, Fizeau interferometer, and Timman Green interferometer. Laser interferometry measurement is one of the effective means to achieve ultra precision measurement and micro nano scale measurement, and plays an extremely important role in many fields. Recently, with the support of national major science and technology projects such as "Large scale Integrated Circuit Manufacturing Equipment and Complete Processes", the research team led by Li Yan, a long-term professor and director of the Academic Committee of the Precision Instrument Department at Tsinghua University, completed the "High speed Multi axis High resolution Laser Interference Measurement Technology and Instruments" project, breaking through a series of key technical bottlenecks and forming new measurement methods, systems, and instruments. According to Director Li, the project has developed a fully chain self-developed high-speed, multi axis large range, high-resolution laser interferometry measurement system, which includes interferometer components, signal detection and demodulation, and multi degree of freedom detection scheme design. At present, the dual frequency laser interferometer system developed by the project team for lithography machines has been applied in the development process of China's self-developed lithography machine workpiece stage prototypes, with a total of more than 50 sets of applications. This research achievement meets the precision measurement requirements of the dual stage prototype of the lithography machine, reduces the dependence on foreign interferometers, lowers the research and development risks caused by export restrictions on its products to China, and plays a positive role in ensuring the smooth implementation of the development of dual stage lithography machines in China. In addition, the sub nanometer resolution traceable heterodyne interferometer developed by the project has also been applied to the comparative verification research of laser multidimensional measurement system research and development. The sub nanometer resolution traceable heterodyne interferometer can identify the causes of nonlinear errors in laser multidimensional measurement systems and correct them with specialized circuits, improving the performance of related unit laser multidimensional measurement systems. The new method of traceable interferometry proposed by the development team has contributed to redefining the Mohr unit using Avogadro's constant. It is worth mentioning that in the past, China did not have the core technology to develop laser interferometry measurement instruments. However, the success of this project has broken the restrictions and monopolies of foreign countries on China's laser interferometry measurement instruments, enriching the theory and technology of laser interferometry measurement in China. This means that in the future, China's equipment and instrument research and development will have stable performance and will not be restricted by foreign measurement and traceability capabilities. In summary, the research findings have significant technical, economic, and social benefits. Laser interferometry measurement technology is an important way to ensure traceable nanoscale measurement, and it is also a key metrology and testing technology to promote China's move towards becoming a strong metrology and manufacturing country. I believe that with the continued in-depth research of the R&D team, China's laser interferometry measurement technology will continue to improve, bringing more benefits to our country.