A heat and mass transfer model was established for the coupled heat transfer process involving regenerative cooling and film cooling in a specific liquid oxygen/kerosene rocket engine, and numerical simulation calculation was made. To comprehensively consider the heat and mass process such as convection heat transfer, radiation heat transfer, thermal conductivity, deposition thermal resistance, evaporation and entrainment, the thrust chamber was divided into three areas, the heating section, the evaporation section, and the gas film section to be calculated. The influences of the liquid film mass flow rate, the injection position of the liquid film and the mass flow rate at each liquid film inlet on the regenerative and film cooling characteristics were analyzed. The results show that: (1) When the liquid film mass flow rate is small, an increase in the liquid film mass flow rate does not significantly change the composite cooling characteristics, but the length of the liquid film zone becomes longer. (2) In the regenerative and liquid film cooling, the different injection positions of the liquid have a significant impact on the wall temperature. As the injection position of the liquid film moves towards the throat, the heat flux density and wall temperature at the throat decrease. (3) Film and regenerative cooling can effectively reduce the wall temperature. The cooling liquid film can significantly reduce the wall temperature and heat flux density. Meanwhile, the gas film formed by the evaporation of the liquid film and the deposited carbon can effectively provide cooling protection for the wall.