Abstract: The joint stiffness of missile cabins jointed by circlip has an important effect on the performance of missile. The main factors affecting this joint stiffness are the asymmetry of the circlip, the friction of contact and pretightening force of the set screws. The influence law of the above three factors on the tensile stiffness, flexural stiffness and local stiffness of the joint is studied by finite element analysis. The simulation studies show that when the frictional coefficient increases from 0 to 0.2, the overall tensile stiffness and the local stiffness of the joint increase by 6.9% and 20.7% respectively; while when the magnitude of pretightening force increases from 0 N to 7 kN, the overall tensile stiffness and flexural stiffness increase by 6.6% and 6.8% respectively. The overall tensile stiffness, flexural stiffness and local stiffness at the notch side decrease by 18.2%, 22.7% and 11.8% respectively owing to the asymmetry of circlip. The study provides a reference for improving the joint stiffness of the missile cabins jointed by circlip.