Abstract: The mechanical behavior of 10CrNi5MoV steel in the two-phase region has been investigated using the gleeble-3500 thermal simulation tester. It is concluded that the yield strength and rheological stress of 10CrNi5MoV steel increase with the increase of strain rate when the test temperature is certain, and decrease with the rise of temperature when the strain rate is certain, and that the degree of decrease is related to the temperature and phase composition. According to the experimental results, the Johnson-Cook (J-C) constitutive model of 10CrNi5MoV steel in the two-phase region is established, and the influence coefficient of temperature is corrected, which effectively reduces the average relative error of the original J-C constitutive model. The corrected J-C constitutive model has a better fitting effect on the mechanical behavior of 10CrNi5MoV steel in the two-phase region.