The effect of metal nanopowders (Al, Fe, W, Ni, Cu, and Cu-Ni alloys) on the decomposition of energetic materials (HMX, AP, and AN) with DTA-TGA method was studied and it was found that the catalytic action appears in the case of Cu-Ni nanopowders with the three studied energetic materials. The temperature of decomposition of energetic materials with the addition of metal nanopowders could be lowered by 82 degrees C for AN, 161 degrees C for AP, and 96 degrees C for HMX. The reaction mechanism of metal nanopowders enhancing the decomposition of energetic materials is discussed.