Abstract: To study the effects of cryogenic treatment on the microstructure and properties of ZG06Cr13Ni4Mo martensite stainless steel, the specimens were divided into six groups, and the tensile properties and hardness of each group were measured by varying the different cryogenic time (0, 12, 18, 24, 30 and 36 h).Metallographic microstructure and tensile fracture morphologies of each group of specimens were observed. The results show that suitable cryogenic parameters promote the transformation of retained austenite to martensite and refine the grain, thus the strength and hardness of the material are improved. When the deep cooling time is 18 h, the mechanical properties of the specimen have achieved the optimum value, the tensile strength and yield strength have reach 1109.0 MPa and 937.7 MPa, respectively, and the hardness reaches 36.8 HRC.