A novel polycyclic caged compound, tetranitrodiazidoacetylhexaazaisowurtzitane (TNDAIW), has been synthesized by a six-step reaction. The molecular structures of two key intermediates and TNDAIW were identified. The crystal structure of the titled compound was established by X-ray crystallography. Semi-empirical MO calculations were performed with AM1 and PM3 methods based on the crystal structure. The corresponding data of beta-CL-20 are also given for comparison.