Abstract: The cyclic deformation behaviors of high strength rail steel were experimentally investigated under uniaxial and non-proportional biaxial compression-torsion cyclic loading at room temperature. The effects of loading paths on the ratcheting behaviors of the high strength rail steel were discussed. The results show that the high strength rail steel exhibits obvious cyclic softening effects and ratcheting behaviors in the compression direction. Moreover, the evolution of ratcheting behaviors depends strongly on loading paths, and the ratcheting strain under an elliptical loading path has the minimum value among five typical loading paths. At the same time, a non-proportionally multiaxial cyclic plasticity constitutive model can be developed based on the Abdel Karim-Ohno non-linear kinematic hardening rule. In addition, the effects of loading paths on ratcheting behaviors were addressed by introducing a non-proportional factor into the kinematic hardening and isotropic softening rules. The comparison of simulations with experiments demonstrates that the extended model can rationally describe the non-proportionally biaxial compression-torsion ratcheting behaviors of the high strength rail steel.