For the leakage problem of the sealing surface of the subsea flange connector,the flow factors of the isotropic rough surfaces were used to modify the parallel plate leak model,and the relationship between the film thickness ratio and the leaking rat was established.By using MATLAB and COMSOL software,the contact surface entity was generated,three root-mean-square(RMS) roughness surfaces were analyzed by finite element method at four operating temperatures,and the relationship between the average contact pressure of rough surface and the film thickness ratio was obtained.The relationship between the average contact pressure and leakage rate of three rough surfaces at four operating temperatures was established by mathematical derivation and curve fitting.The results show that the operating temperature has a great influence on the surface quality requirements of the lenticular gasket.When the operating temperature is from 20 ℃ to 100 ℃,the lenticular gasket with RMS roughness of 0.4 μm can meet the requirements of the leakage rate index,while when the high temperature oil production operation is from 100 ℃ to 150 ℃,only the RMS roughness of 0.2 μm can meet the leakage rate index requirements.