In order to study the influence of random material and geometrical parameters of rubber gasket caused by machining error on waterproof performance of shield tunnels lining joint, material hardness, coordinates of the bore center and diameter are selected as the random input variables, targeting the surface average contact pressures of gasket, to calculate the sensitivity values to contact pressures of all these random parameters by using the ANSYS PDS module. The results from an analysis of elastic gaskets used in a certain city metro shield tunnel show that rubber mechanic parameters are principal factors, especially C10. Among geometric parameters, there is more influence on down surface contact stress because of the variation of upper bores diameter in the section. However, positions of bore are sensitive to near surface contact stresses, and the variation of middle bores have almost the same influences on both surfaces.