In safety experiment of explosive charge，just only the curve of droping hammer impact loading is similar to the one of chamber pressure，so the result of droping hammer impact test is very significant. There are many factors about load characteristics of droping hammer impact，by the adjustment of various factors，the curve of droping hammer impact loading coincide with the chamber pressure，it’s the premise of safety experiment of explosive charge with droping hammer method，and it’s also difficult. In this paper, we use ANSYS / LS-DYNA nonlinear finite element analysis software to simulate the change pressure in the internal explosive charge on the droping hammer impact loading. By changing the height of drop hammer, the weight of droping hammer and the height of explosive charge, we study the dynamic response (pressure) in the internal explosive charge. Numerical simulation results show that the height of droping hammer, the weight of droping hammer and the height of explosive charge has an impact on the pressure in the internal explosive charge; the weight of droping hammer and the height of explosive charge has an impact on the width of pressure pulse time, but not include the height of droping hammer.