This research describes the influence of nano-sized aluminum with varying contents (0-20 wt%) on the combustion behaviors of HMX/GAP/Al in aspects such as burning rate, surface temperature, gas phase temperature, mole fraction of species, and specific impulse. A rigorous mathematical model is developed for three phases (solid phase, condensed phase, and gas phase) with detailed kinetics. This model consists of 507 gas phase reactions and 4 condensed phase reactions of HMX/GAP/Al combustion. The model also emphasizes the phase transitions and reactions of aluminum in the gas phase. Based on this model, dynamic simulation is carried out at various propellant compositions and operating pressures by means of the moving boundary approach using gPROMS software package. The simulation results are in close agreement with the experimental data at slight marginal errors for HMX/Al combustion, predicting the combustion behaviors for the HMX/GAP/Al system. Accordingly, the model predicts the gas phase temperature of 3061 K for the 20 wt% Al and the specific impulse of 258.53 s for the 15 wt% Al of HMX/GAP/Al propellant under an operating pressure of 100 atm. The increase in burning rate and specific impulse by increasing the pressure is also indicated. According to this study, the addition of aluminum particles with a content range of 15-20 wt% considerably improves combustion behaviors. By dynamic modeling and simulation, a detailed framework for studying the multi-phase combustion of aluminized solid propellant is introduced. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.