Studying how and how much the factors affect on the cooling rate of workpieces is very significant to improve the ability of vacuum high pressure gas quenching furnace. From changing the structure and technology of nozzle-type vacuum high pressure gas quenching furnace, by a large number of computer simulation, this paper discusses some factors affecting the cooling rate. By changing the number and distance of nozzles on each wind pipe, we can better control the cooling rate and uniformity of workpieces. From the perspective of improved process, the number, shape, size and placement of the workpieces have certain effects on cooling rate, in which the placement of the workpiece is very significant and significant. The simulation results for the further development of new high-pressure gas quenching vacuum device provide a theoretical basis.