Abstract: In order to study the parameter optimization of mine combined ventilation system at high altitude, a copper mine in Tibet was taken as background, by using fluid mechanics software-FLUENT, the concentration distribution of dust in the excavation roadway under different ventilation environment was simulated based on the gas-solid two phase flow theory. By changing combined ventilation parameters including pressure volume, location of ventilation tube and pumping air volume ratio, the influence of the ventilation parameters on dust transport was summarized to optimize the combined ventilation parameters. The simulation results: when the pressure volume is 150 m³/min; pressure tube and ventilation tube outlet is respectively at a distance from the heading face for 14 m and 2 m; pumping air volume ratio is 0.9, the concentration of dust was reduced greatly. The numerical simulation results are roughly in line with the actual situation through the field experiment.