Factors which affect regression rate in solid fuel ramjet (SFRJ) are explored through theoretical analysis.The exponent relationship of the mean regression rate with combustor pressure
inlet air mass flux and air temperature is derived.SFRJ model based on combustion and flow is established.Then the regression rate is simulated numerically by using PHOENICS software.Comparison between the calculated results and the experimental data confirms the eorrectness and reliability of the presented simulation method.