In order to analyze the stressstrain field characteristics of rails,a threedimensional elasticplastic rail model is established by finite element method.The results show that the stressstrain field of rail at the contact patch is in a threecompressionstress state,with much greater hydrostatic stress.Rail rolling contact fatigue (RCF) crack initiation life is very sensitive to hydrostatic stress. Based on the critical plane approach,a new prediction model is established by taking into the consideration the effects of hydrostatic stress on the rolling contact fatigue crack initiation life.An analysis is made of the effects of wheel load and friction coefficient on the basis of the model. U71Mn rail steel is investigated in detail to validate the proposed approach. The results show that,as the hydrostatic stress increases,the effects of hydrostatic stress on the rolling contact fatigue crack initiation life become greater and as the wheel load and the friction coefficient increase,fatigue life to crack initiation decreases significantly.