Abstract: The components test and room temperature tensile experiments of the rare earth steel and U75V heavy rail steel were carried out. On the basis of ensuring the quality and mechanical properties of the test materials which meet the standard requirements, the fatigue test and fracture observation of the above steels were carried out, then the fatigue properties were carried out. The results indicate that the fatigue life curve（S-N curve） of the two materials decrease rapidly under the large force. The slope of curve is smaller and the life is longer with the reduction of external forces. Overall, the rare earth steel has a longer life than that of U75V heavy rail steel under the same force.