As a new technology for cutting⁃edge automated drilling, Rotary steer drilling technology has become an indispensable technology for complex ultra⁃deep drilling and large⁃displacement wells. To break the foreign monopoly, Shengli drilling institute has developed a stable platform based on the Strapdown algorithm. The servo technology is used to control the action implement of the guidance mechanism, and the optimization and improvement of the uploading and downlink communication system are optimized and improved, so as to realize the independent research and development of the strap⁃down dynamic push⁃to⁃rotate guiding system. At the same time a set of tool well test platform is designed to test its pushing performance and verify the accuracy of the design. On this basis filed test have been done in four wells, and the results show that the system's deflection ability can reach 6.43 ° / 30 m, with good practicability, stability and reliability. This paper mainly discusses the design process and ideas of strap⁃down rotary steering, introduces its main structure and design key points, and describes the uphole test platform and downhole experiments. The content of this paper summarizes the development of strap⁃down rotary guiding technology, and plays a positive guiding role for the further optimization and improvement of rotary guiding system technology.