The work aims to study initial fatigue micro-crack behavior on rail surface which is subjected to cyclic wheel/rail loading under plastic stresses. A 2D finite model of rail with a surface crack was established. The corresponding nodes of the crack surface were coupled to achieve the effect without crack. After several cyclic loading, the joint coupling was released to show the crack. The residual stress intensity factor was calculated by analyzing the response of rail by cyclic wheel/rail loading. The initial fatigue crack growth rate was also calculated by stable stress intensity factors in the asymptotic state (As the number of cycles increased, the new plasticity in the crack tip became smaller and smaller, and the plasticity did not increase within the small range of crack tip). In the finite element simulation, the rail was subjected to cyclic wheel/rail loading to produce tensile residual stress on the upper surface, and the tensile residual stress became smaller and smaller with the increase of depth. After crack initiation, the residue (KI) of crack at different angles decreased with the increase of cyclic number, but residue (KII) increased with the increase of cyclic number. Under the influence of residual stress, the stable stress intensity factor of initial micro-crack on rail surface in the asymptotic state increased with the increase of crack angle (θ). The residual stress on the rail surface accelerates the propagation rate of the initial micro-crack and reduces the service life of rail.