The combustion performance of composite solid propellants (CSPs) significantly affects their application in the field of military and civil aircraft. Ammonium perchlorate/hydroxylterminated polybutadiene (AP/HTPB) composite propellants are one of the common CSPs, and their combustion performance is mainly affected by AP thermal decomposition. In this work, a simple strategy was put forward to effectively construct MXenesupported vanadium pentoxide nanocomposites (MXene/V 2 O 5 , MXV). MXene provided a good loading interface for V 2 O 5 nanoparticles, which made MXV obtain a large specific surface area and simultaneously improved the catalytic performance of MXV for AP thermal decomposition. The catalytic experiment results showed that the decomposition temperature of AP mixed with MXV (MXV-4, 2.0 wt %) was 83.4 °C lower than that of pure AP. Moreover, the ignition delay of the AP/HTPB propellant was significantly reduced by 80.4% after adding MXV-4. The burning rate of the propellant was also increased by 202% under the catalytic action of MXV-4. Based on the above results, MXV-4 was expected to be an additive for optimizing the burning process of AP-based composite solid propellants.■ HIGHLIGHTS 1. MXene/V 2 O 5 (MXV) nanocomposites were effectively constructed by a simple strategy. 2. MXV-4 showed a special uniform porous structure with a large specific surface area. 3. Ignition delay of the AP/HTPB propellant was reduced by 80.4% after adding MXV-4. 4. MXV-4 increased the mass burning rate of AP/HTPB propellants by 202%.