Abstract A kind of numerical simulation method for turbulent combustion in underwater vehicle combustor is presented. The numerical simulation is described with κ−ɛ standard turbulence model, eddy dissipation combustion model and discrete droplet model for liquid. Velocity field, temperature field and concentration field are obtained. The effect of inlet pressure difference in spray for the combustion is analyzed. It draws conclusion through simulation: as pressure difference grows, the spray characteristic enhances, the combustion efficiency increases. The simulation result provides a reference for the optimization of the underwater vehicle combustor.