Abstract: At microscopic scale, the 1, 3, 5-triamino-2, 4, 6-trinitrobenzene(TATB)/polymer bonded explosive (PBX) was regarded as a three-phase composite, consisting of TATB particles, polymer matrix and voids. Based on the microstructure of PBX, a representative volume element (RVE) model was developed by the Monte Carlo method. The finite element model (FEM) was built considering the fraction and distribution of the fillers and pores based on the RVE model. The effect of filler fraction, porosity and pore distribution on the effective thermal conduction of TATB/PBX was studied. The results show that the effective thermal conductivity of TATB/PBX increases with TATB volume fraction increasing. At the same TATB volume fraction, the increase of porosity leads to the exponentially reduction in thermal conductivity of TATB/PBX, but the pore spatial distribution has little effect. The good consistence between simulation and experimental results proves that the model can be used to predict the effective thermal conductivity of TATB/PBX by comparing the predicted and the experimental results.