To make sure a DNAN based composite explosive safe on the casting process, the RZD-1 explosive was investigated as the object and the risk factors and categories were obtained due to analysis of process safety. By means of simulation and trial tests, the safe factors such as explosive substantial safety, compatibility, heat stimulating etc were observed and analyzed. The results came out that the explosive formula was safe essentially, the mechanical sensitivity (≤40%) was competent for the casting process even if the solid ingradients in the formulation were damaged by heat, and the formulation met the needs of safe usage. The internal temperature rise in the process of melt admixture and condensation was less than 3.5℃ all the time, that is, the heat explosion would not happen and the casting process of a DNAN based explosive was proved to be safe.