Based on the detonation velocities of a series of cast polymer bonded explosive(PBX) formulations, a linear relationship was obtained by fitting the data between detonation velocity and HMX content. Both the influence of HMX particle property and the composite deterrent content on the mechanical sensitivity were investigated. Using high quality HMX as major explosive, the safety of composite explosives was the best when adding 3% composite deterrent. Then a new HMX based cast PBX explosive GO-1 with high solid loading content was designed, and its friction sensivity, impact sensivity, shock-wave sensivity, detonation velocity and Gurney coefficient were 5%, 0, 17.7 mm, 8587 m·s^-1 and 2.80, respectively, which showed perfect on safety, detonation velocity and ability for accelerating metal. And in the low vulnerability examination including bullet impact test, slow cook-off and fast cook-off test, all the reaction grade were combustion. So the new explosive has wide application foreground in fragment and EFP warhead.