In order to research the influence of uncertain parameters on the static strength of planet carrier, we took the relief cut as the research object, and found out sensitive parameters from uncertain parameters using the standard deviation analysis method. D-OPT method was used to sample these parameters, the maximum principal stress was calculated by using fine FEM model, and then the polynomial response surface could be build based on these samples. Based on the fast response surface function, the Monte Carlo method and the statistical analysis were introduced to analyze the influence of sensitive parameters (interference, blend R1 and thickness tolerance) on the maximum principal stress, and the reliability of the static strength was evaluated. The results show that the discreteness of the interference and the thickness tolerance has obvious influence on the static strength. And the reliability of the planet carrier reaches 99.3%, which means the reliability is very high even if the reduction coefficients of GL and IEC are considered.