By analyzing the possible synthetic routes of hexanitrohexaazaisowurtzitane(HNIW), it′s concluded that a three-step strategy is practical, i.e.,the first,synthesis of benzyl-derivative of hexaazaisowurtzitane,then,transformation of the N-benzyl substituents into intermediate with N-carboxyl groups and at last,nitration of the intermediate. The three-step synthetic states is reviewed and discussed,and the synthetic information about hexanitrohexaazaisowurtzitane in several countries is given.