To analyze regular of the shift from internal elastic strain to plastic stain for polymer-bonded explosive (PBX), creep curves for HMX based PBX under 80 ℃ were obtained by time temperature equivalence principle, and the creep model based on modified time hardening theory was obtained by ANSYS software. The deformation of HMX based PBX during the thermal-pressure process was simulated. Results shows that compression deformation occurs along the loading stress under thermal-pressure aging treatment(80 ℃, 10 MPa) for HMX based PBX with diameter and height reducing 0.476 mm, 1.306 mm, respectively, and the density increasing 0.047 g·cm^-3, which confirms that the creep behavior of PBX can be accelerated by the thermal-pressure aging treatment.