Powder Metallurgy is an important part of the forming process for metal materials. However, most material models are not able to simulate the variation of mechanical characters during the compressing process. In this paper, the Drucker-Prager/Cap model is modified by including the fully densified metal yield strength. This modified Drucker-Prager/Cap model can limit the yield strength of metal powder within the Von Mises surface of a fully densified metal. With the compressing process, the powder’s surface is infinitely close to Von Mises surface. By comparing of the model prediction and the published experimental results, this modified model works well in terms of accuracy. And, it is applied to the simulation of a hot isostatic pressing for a supper alloy. The prediction of the deformation as well as the stress distribution by this model is more accurate compared to the real test than that by the traditional Drucker-Prager/Cap model.