This article uses FLUENT software to simulate the oxy-fuel supersonic flame spray（HVOF）process. With the development of computer technology,the simulation of HVOF combustion state and gas flow field can optimize physical parameters and guide gun body design,which has become a research hotspot in recent years. However,research on the combustion process of mixed fuel has yet to be deepened so far. Therefore,this paper uses the mixed gas of propane and hydrogen as fuel to carry out the numerical simulation of the combustion process of HVOF,and compares the simulation results with the pure propane gas combustion process. Furthermore,the combustion state of HVOF and the state of gas flow field were compared under the conditions of 90 mm nozzle and 110 mm nozzle length. The simulation results show that the addition of hydrogen in the mixed gas makes the combustion body have the advantages of high energy density and concentrated heat generation,which has a significant impact on the combustion process and the concentration of the gas flow field. The longer nozzle creates greater binding force to the gas flow field and burns. The combustion in chamber is more complete,at the same time,exit of the gun have significant shock waves.