Ultra-high-speed rail facilities are a typical example of China's creation. High-level technologies such as super high-speed rail and vacuum pipe trains lead the world's transportation technology trend. For ultra-high-speed rail transit equipment with speeds greater than 2000km/h, unprecedented high-precision requirements will inevitably be imposed on the spatial position of the track structure carrying it. The geometric shape of ultra-high-speed track is different from the straight line characteristics based on the surface horizontal plane of conventional high-speed railway tracks. It presents the spatial straight line characteristics based on the earth's tangent where the track is laid. How to ensure the actual geometric shape of ultra-high-speed track and the theoretical spatial position of ultra-high-speed track. The minimum error, that is, the high-precision measurement and adjustment control of track smoothness, and then the corresponding construction technology is determined. There is no mature and complete measurement and control theory at home and abroad, and there is a lack of corresponding construction technology. This series of problems is at the international forefront. In order to promote the rapid and sustainable development of ultra-high-speed track technology and equipment, the research team has carried out research and application on key technologies for high-precision measurement and control of ultra-high-speed track smoothness for more than 6 years. By building theoretical models and algorithms, it has proposed a track with independent intellectual property rights. High-precision measurement and control technology and construction technology have achieved a leap from basic research, engineering innovation to engineering application. The main innovations are as follows: (1) First proposed a micrometer-level high-precision ultra-high-speed track geometric calculation model. Aiming at the problem of high-precision measurement of orbital geometry and spatial straight lines, a coordinate conversion and solution algorithm between the measurement system spherical coordinate system and the orbit three-dimensional spatial coordinate system that considers compensation for the radius of the earth's ellipsoid is innovatively proposed; A time-domain spatial inversion method for ultra-high-speed track geometric irregularities spectrum has been established, which reveals the influence mechanism of track geometric irregularities on the service status of ultra-high-speed track facilities, and breaks through the high-precision measurement of ultra-high-speed track geometry and its coupled dynamics. Related bottleneck issues. (2) Invented and developed ultra-high-speed track smoothness measurement and adjustment equipment. In response to the outstanding key issues of high-precision measurement and control of linear coordinates in track geometric space, we first proposed a method for high-precision positioning and measurement of linear coordinates in ultra-high-speed track geometric space using laser tracking and control, and developed special construction supporting devices such as gun limit phase instruments. Based on the research results of the coupled dynamics of track smoothness, a construction process for high-precision geometric measurement and control of ultra-high-speed tracks is proposed, which solves the practical construction problem of track geometry and position micron line measurement and control. The track geometry and position construction accuracy of 0.2mm reaches the international leading level. level. (3) It is the first time to propose a construction technology for controlling welding smoothness of ultra-high-speed seamless track rails and releasing stress after locking. Equipment such as rail jaw refiners for welded joints has been developed to solve the problem of controlling the inherent quality and appearance accuracy of large-section rail welded joints. The flatness of the joints reaches plusmn;0.1mm required for ultra-high-speed special tracks. In view of the construction problems such as high locked rail temperature, long bleeding lines, and difficult construction organization, the single-strand divided drum free bleeding method was innovatively used to relieve the overall stress of the seamless line, and a construction organization method for ultra-high-speed rail seamless lines was proposed. For the first time, the construction of ultra-high-speed rail seamless lines under the condition of a large temperature difference of 80 degrees was realized. Research on high-end core technologies focusing on high-precision measurement and control of ultra-high-speed track smoothness, and obtained a series of original results. After reviewing the scientific and technological achievements of China Railway Corporation, the high-precision measurement and control technology of ultra-high-speed track smoothness has reached the international leading level. This achievement has been applied to the laying and construction of a 9km ultra-high-speed track in China. The test speed has reached 3672km/h, and all parameters of track smoothness meet the test requirements. Published 17 high-level papers on core technology, applied for and authorized 3 national invention patents, 9 utility model patents, and 1 soft book, which has aroused strong interest from relevant companies at home and abroad. The direct economic benefits of new technologies were 77 million yuan, new profits were 3.85 million yuan, and new taxes were 5.39 million yuan.