The gas drying furnace is an important industrial drying furnace. The heating process is required to be stable in the design of the drying furnace. By analyzing the heat transfer characteristics of the heating process, the stability of the heating process is determined by the distribution of the hot gas flow field. The numerical simulation of the flow field of the air duct is simulated by FLUENT, and the position of the plate windshield is changed by changing the position of the plate. The influence of the plate windshield on the flow field distribution is compared and analyzed. The characteristics of the outlet of the air duct reflect the distribution of the flow field of the air duct and the characteristics of the flow field around the workpiece. Accordingly, the effective measures to improve the distribution uniformity of the flow field are obtained, and the method of improving the stability of the heating process is realized, and the requirements for the design of the drying furnace are put forward. Way.