The hot deformation behavior of 50Cr5NiMoV backup roller steel was systematically investigated by single-pass compression tests at the deformation temperature of 950-1150 ℃, the strain rate of 0.01-1 s-1, and the deformation amount of 50%. The test results show that the rheological stress decreases with the increasing of deformation temperature and increases with the increasing of strain rate. Based on the true stress-strain curves, a strain-compensated Arrhenius model was constructed, and the polynomial relationship between material constants and strain was obtained by fitting. In addition, the dissipation efficiency map and hot processing map were constructed for different strain levels, The results show that the optimal processing zone is 1075-1150 ℃ and 0.01-0.22 s-1. On this basis, the free forging simulations were carried out in the safe zone and the unstable zone of the hot processing map, respectively. The simulation results show that the forged workpiece in the unstable zone mainly exhibits a triaxial tensile stress state, while the forged workpiece in the stable region is mainly subjected to a triaxial compressive stress states. Thus, the research results provide a theoretical basis and test support for the optimization of the hot processing process of 50Cr5NiMoV backup roller steel, which has significant engineering application value.