Abstract: The performance study of flexible spring which is used for cryogenic refrigerator has not formed a complete analysis method.Many literatures have just analyzed from two aspects：stress limit and stiffness of flexure spring. Therefore，it appears to be very valuable to further study the properties of flexure spring in other aspects.In this paper，the fatigue life of Sunpower spring was estimated，and the damage and the safety factor chart was simulated by Ansys software.The damage location of flexure spring could be obtained.At the same time，a variety of processing technologies are analyzed and the flexure spring was etched chemically，and the axial stiffness of flexure spring was tested by the TSL series tension and compression testing machine.The results showed that material hardness does not affect the stiffness of spring.