In order to explore the effect of aluminum (Al) on the performance of 1,3,5-trimethylene trinitramine (RDX), the process of RDX/Al/NC composite explosives prepared via an electrostatic spraying method was simulated using ANSYS software, and the simulation data such as the velocity profile and particle size distribution were obtained. RDX/Al/NC composite explosives with different ratios were experimentally prepared, and the morphology, structure, thermal properties, combustion properties and impact sensitivity of the samples were measured. The simulated particle sizes of the RDX/Al/NC composite explosives with 15%, 35% and 55% Al contents were concentrated at 1427 nm, 3250 nm and 5428 nm, respectively. Experimental results showed that the experimentally prepared particles were slightly smaller than their simulated counterparts, yet both datasets revealed the same trend. The physical recombination of RDX, Al and NC was observed in composite explosives. Compared with the raw material RDX, the activation energy of the RDX/Al/NC composite explosives decreased, the critical temperature of thermal explosion increased, the impact sensitivity decreased, and the combustion performance improved. The activation energies of the RDX/Al/NC composite explosives with 15%, 35% and 55% Al contents reduced by 45 kJ mol⁻¹, 48 kJ mol⁻¹, and 67 kJ mol⁻¹, respectively, and the critical temperature of thermal explosion of the RDX/Al/NC composite explosives with 15%, 35% and 55% Al contents improved by 9 K, 3 K and 4 K, respectively.