The fatigue performance of EA4T axle steel in corrosive environment was studied to provide the basis for corrosion detection and service life evaluation of axle. The fatigue test of EA4T axle steel specimen was carried out by rotating bending fatigue testing machine in air environment and corrosive environment simulated by artificial rainwater to get the fatigue S-N curves, surface damage and crack propagation of the samples under different environments. Then the probability of crack propagation was calculated. The fatigue failure fracture was observed by scanning electron microscopy, and the change of crack growth threshold in different environments was analyzed and compared. The fatigue limit of samples in the air environment was 355 MPa, while in the corrosive environment, there was no fatigue limit. The fatigue strength corresponding to 107 cycles was reduced to 245 MPa, which was 31% lower than that in the air environment; Gumbel distribution statistics was more suitable than Weibull distribution statistics to describe the change of corrosion crack length on EA4T axle steel specimen surface with loading times; In corrosive environment, fatigue cracks originate in surface corrosion pits, and multiple crack sources exist; The threshold value of crack growth in corrosive environment was significantly reduced, which was 6.29 MPa.m1/2 in air environment and 4.1 MPa.m1/2 in corrosive environment. Corrosion environment reduces fatigue life of EA4T steel mainly because it reduced the threshold of crack propagation, accelerated crack initiation and short crack propagation, when the crack reached a certain length, corrosion environment had little effect on crack propagation.