Abstract: The cryopump casing is an important component in the large-scale fusion reactor cryopump,and the structure and performance of pump casing directly affect the working efficiency of cryopump. Herein,we reported the design, structural statics analysis,modal analysis and transient dynamic analysis of pump casing. The results showed that the maximum deformation of the cryopump casing under the combined working condition occurs at the welding position between the front flange and the cryopump casing wall,which is about 1.4×10^-2 mm,and the maximum stress of about 3.99 MPa occurs at the edge of the front flange,both of which meet the engineering design requirements of the cryopump casing. The design of pump casing provides methods for the development of cryopumps.