Abstract: In order to improve the accuracy of numerical simulation of forging, taking the 3Cr2MnNiMo plastic die steel as the research object,according to the actual forging process and the internal structure characteristics of the ingot, the whole model and partition model were established by ABAQUS finite element simulation software. The numerical simulation of forging process was carried out by using the axial repeated upsetting-stretching method with two upsetting and two stretching.The temperature field, stress field and surface forming quality of two blank models during forging process were compared and analyzed. The results show that compared with those of the partition model, the temperature distribution of the whole model after forging is more uniform and the temperature difference is smaller, the equivalent stress value is smaller,and the surface smoothness and forming quality are better.