The progress in synthesis and engineering manufacture of high energy and density compound hexanitro-hexaazaisowurtzitane (HNIW or CL-20) is reviewed. The advantages

drawbacks and applications of three main approaches to the engineering manufacture of CL-20 based on hexabenzylhexaazaisowurtzitane(HBIW) intermediate are discussed

the difficulty in developing new synthetic routes for CL-20 is also analyzed. The result shows that the synthesis and nitration efficiencies of the new isosowurtzitane precursor are low

and its cage-dimensional structure is easily broken. The developing tends on lowering CL-20 production cost is to seek new efficient catalysts and explore new synthesis routes.