The liquid quantity required(LQR)for liquid quench of solid rocket motor was determined with the use of a theoretical model developed by the authors.LQR increases with propellant energy and decreases as the evaporation heat of liquid and the liquid pressure drop(the difference between injection pressure of liquid and chamber pressure)increase.The effects of the chamber pressure and burning rate pressure exponent of propellant on LQR merge into the effect of mass burning rate of propellant.Then LQR increases with increasing mass burning rate.The theoretical results are in good agreement with experimental data.