The compressive behaviors of 30Cr2Ni4MoV rotor steel were investigated at the temperatures from 1223 to 1523 K and strain rates from 0.001 to 0.1 s(-1). A modified Johnson-Cook (JC) model was proposed to describe the compressive behaviors of the studied alloy steel. In the modified JC model, the coupling effects of strain, strain rate, and deformation temperature were considered. Comparisons between the predicted stress-strain values by the modified JC model and measured ones indicate a good agreement, which confirms that the modified JC model is valid for the predicting the flow stress of 30Cr2Ni4MoV rotor steel over a wide range of temperature and strain rate.