The accelerated thermal aging tests of PBX based on TATB were carried out by using a hot air oven from 55 ℃ to 75 ℃. The mechanical properties such as tensile strength, elongation at failure and modulus were measured before and after aging. Morphology of rapture section from tensile test at 55 ℃ was observed by using scanning electric microscopy (SEM). Results show that the mechanical properties and the interfacial mechanism between binder and TATB crystal do not undergo changes significant during the aging period.