In this paper，a comprehensive numerical model is presented for simulating combustion process of gas hydrogen and oxygen jet flow in the liquid propellant rocket engine preburner，including the governing equations of combustion processes，k-εturbulece model，EBU turbulence combustion model and auxiliary formula of thermo-dynamic properties. With this model，numerical simulation of the effect of the injector configuration and the jet mode of gas oxygen on the flow，mixing and combustion processes was performed. The numerical results show that the injector configuration and the jet mode of gas oxygen have a significant effect on flow field and combustion performance.