To elucidate the influence mechanism of the mass ratio of ammonium perchlorate （AP） to octogen （HMX） on the combustion performance of nitrate ester plasticized polyether （NEPE） propellants， multiple testing methods including the underwater acoustic emission method， micro-thermocouple technique， coaxial digital holography and condensed-phase product collection method were adopted in this study. The effects of AP/HMX mass ratio （13/50-19/44） on the burning rate， combustion wave structure and condensed-phase product characteristics of NEPE propellants were systematically investigated. The results show that with the increase of AP/HMX mass ratio， the burning rate of propellants increases from 11.4 mm·s^-1 to 12.3 mm·s^-1， the explosion heat rises from 6820 kJ·kg^-1 to 7107 kJ·kg^-1， the thickness of condensed-phase preheating zone decreases from 317.3 μm to 183.6 μm， the burning surface temperature rises from 336 ℃ to 494 ℃， the maximum temperature of gas-phase flame zone increases from 2934 ℃ to 3017 ℃， the median diameter of aluminum agglomerates decreases from 275.86 μm to 209.77 μm， and the active aluminum content in condensed-phase products decreases from 2.55% to 0.86%. The combustion performance of NEPE propellants can be regulated by adjusting the AP/HMX mass ratio via the synergistic action of thermodynamics and kinetics.