In order to better describe the high-temperature tensile deformation behavior of LZ50 axle steel, high-temperature tensile tests of LZ50 axle steel were conducted by using Gleeble-3800 thermal simulation tester at the deformation temperatures of 900, 1000 and 1100 ℃ and the strain rates of 0.1, 1.0 and 10.0 s-1, respectively, and the stress-strain data were obtained under different deformation conditions. Then, based on the modified Johnson-Cook(JC) constitutive model and the multivariate nonlinear regression constitutive model(DMNR), two high-temperature tensile constitutive models for LZ50 axle steel were established. Furthermore, the predicted values of the two established models were compared with the experimental data, and the prediction accuracies of the two established models were quantitatively analyzed by using correlation coefficient R and average relative error AARE. The results show that the prediction abilities of the two models under different deformation temperatures are different, and JC model has better prediction ability at 900 ℃, with the R and AARE values of 0.995 and 1.20% respectively. However, DMNR model has better prediction ability at the deformation temperature of 1000 ℃, the R and AARE values are 0.997 and 6.38%, respectively, and the prediction accuracies of the two models at 1100 ℃ are similar.