Abstract: Uniaxial tensile experiment, symmetry cyclic strain and asymmetric cyclic stress fatigue experiments were carried out to investigate the cyclic characteristic and ratcheting behavior of heat-treated U71Mn rail steel. Based on the experimental results, the Abdel-Karim-Ohno cyclic plastic constitutive model was modified. The simulation results were compared with the experimental results. The results show that the test steel exhibited a cyclic softening characteristic in the initial cycles. The obvious ratcheting behavior was observed under asymmetric cyclic stress loading, and the ratcheting strain increased with the increase of stress amplitude, mean stress and peak stress; the ratcheting strain rate increased with the increase of peak stress; when the peak stress was no more than 950 MPa, the ratcheting strain rate decreased rapidly and approached a stable state with the increase number of cycles; when the peak stress was more than 950 MPa, the ratcheting strain rate first decreased and then increased. The average relative error of ratcheting strain between experimental and simulated values obtained by the modified Abdel-Karim-Ohno cyclic constitutive model under most working conditions was about 9.8%, indicating that the model could reasonably predict ratcheting behaviors of heat-treated U71Mn rail steel in stress cyclic conditions.