Moving boundary problem frequently occurs in chemical engineering to describe various problems when the boundaries to describe domain keep changing. Combustion of solid propellant is a notorious example, which involves three phases (solid, condensed, and gas phase) and the positions of the interface between phases change in relation to the state of phases. In this study, moving boundary modeling approach was suggested to develop a rigorous mathematical model of solid propellant combustion. The mathematical model of a solid propellant was divided into three sub-models for each phase, which include conservation equations (mass, energy, and momentum conservation) and constitutive equations within the framework of moving interface. Coordinate transformation was carried out to achieve a fixed interface formulation from the moving interface problem, which leads to a fixed domain of each phase ranging from 0 to 1. In order to validate the feasibility of this approach, the mathematical model for the combustion of ammonium perchlorate was developed and dynamic simulation was performed with various operating conditions. The simulation results, including burning rate, temperature, mole fraction, and phase thickness, were compared with various reference data. Based on the comparison, it was concluded that the suggested moving boundary modeling approach can be used for the combustion of solid propellant and can accurately predict dynamic behaviors of the combustion. (C) 2017 The Combustion Institute. Published by Elsevier Inc. All rights reserved.