To obtained the influence of high temperature and mechanical stress on the mechanical behaviors of polymer bonded explosive(PBX), the response of HMX-based PBX-1 and TATB-based PBX-2 under the action of different high temperature and mechanical stress were obtaitned based on the results of matrerial testing machine, and their change mechanism of mechanical properties are analyzed by dynamic mechanical analyzer (DMA) and scanning electron microscopy (SEM). Results show that the tensile strength and compressive strength of the two PBXs decrease with temperature increasing under coupled high temperature-mechanical stress loading at 25-90 ℃, but the failure strain undergos saltation at some temperature point, which is about 65 ℃ for PBX-1 and 35 ℃, about 55 ℃ and 75 ℃ for PBX-2. The response rule of PBX-1 subjected to sequence high temperature-mechanical stress loading contains two temperature ranges, 25-150 ℃ for the first stage, the compressive strength and failure strain of materials under the action of the high temperature in the range almost do not change, 150-200 ℃ for second stage, the failure strain increases with the increase of temperature, the compressive strength first decreases and then increases, which is lowest at 180 ℃. Under coupled high temperature-mechanical stress action, the phase change of binder and its change of viscoelastic characteristics is the main reason affecting the high temperature softening and deterioration of machanical properties of PBX. The deformation behaviors of PBX, especially its saltation of tensile failure strain and compressive failure strain are caused by softening-flow-viscous flow. At the same time, the failure mode of PBX changes from brittle fracture to debonding failure and the saltation temperature of PBX corresponds to the transition temperature of the state of matter for binder. For sequence high temperature-mechanical stress loading, the elastic recovery of binder and explosive crystal without damage is the main reason for no change of the mechanical properties of PBX-1 at 25-150 ℃. The crushing of explosive crystals occurs at high temperature around 180 ℃, leading to the compressive strength of PBX-1 reaches the minimum at around 180 ℃.