Based on the tensioning characteristics of spring, the spring insert anti-loosen nut still has good anti-loosen performance in the state of small tightening moment or no moment, and the residual axial force is not less than 70% after 1200 transverse vibration tests. The spring nut body material is 304B high-quality austenitic stainless steel, the performance grade is A2-70, and the thread is treated by reliable anti seizing process.