A new initiating explosive－tetraamminediazido cobalt(Ⅲ) perchlorate(DACP) was synthesized. Its structure was characterized by the IR，¹HNMR etc. And the main properties were measured by the various methods. The results show that DACP is an excellent primary explosive similar to tetraamminebis(5－nitrotetrazolato) cobalt (Ⅲ) perchlorate (BNCP) in functions. Synthetic method of DACP is much simpler than that of BNCP. In some initiating devices, DACP may be a substitute for BNCP and Pb(N₃)₂.