The effect of change of load,gap between the pin and plate hole and frictional coefficient on the maximum contact stress was studied. FEA result was compared with several formula calculation results. When the gap of pin and hole△R = 0,the average bearing stress formula can be adopted; when the ratio of gap between the hole and pin to radius of the pin λ≥0. 02,in order to save cost for FEA analysis the Hertz formula can be adopted if no other more accurate calculation methods are available The computing error between the Hertz formula and FEA is less than 10%.