Thermal decomposition effects on internal temperature field of explosive cylinders during accelerated aging test was investigated by theoretical analysis, which indicated that main factors are explosive type, test temperature and sample size. Then, internal temperature field of five explosive cylinders, hexogen(RDX), triamino trinitrobenzene(TATB), Tetryl, cyclotetramethylenetetramine(HMX), pentaerythritol tetranitrate(PETN) with different size under different temperature were simulated by finite element analysis. Results show that explosive cylinder type is the key factor of the effect on internal temperature field. Temperature deviations of RDX and PETN cylinder(Ф20 mm×20 mm) at 110 ℃ are 2.59 ℃ and 1.19 ℃, respectively. And, the test temperature and size of explosive cylinders should be rationally controlled to reduce the temperature deviation for explosive cylinders of RDX, PETN.