A modelling of the high-pressure hypergolic bipropellant combustion process for liquid rocket engine is presented in this paper. The modelling takes account of the decomposition reaction of UDMH，dissociation reaction of N₂O₄，highpressure vaporization，secondary atomization of mixture ratio and flow flux in the cross-section of the combustor. As an example of the application of this model，the combustion efficiency and energy release distribution of 3 injectors for FY-2 Engine are calculated in theory. The calculated results are in good agreement with the experimental data.