The problems of unstable product quality and low drying efficiency of a heat pump drying room used in the drying process of chrysanthemum were investigated and tested. With the help of computational fluid dynamics (CFD) simulation software, the numerical simulation of airflow distribution in the drying room was carried out, and the uniformity of velocity distribution was analyzed. The results showed that under the condition of no load, the airflow distribution in the drying room was better when the tilt angle of the guide plate was set at 15°. The airflow uniformity was better when the exhaust wind speed was 6m/s. The comparison showed that the exhaust velocity had the greatest influence on the airflow in the drying room. Under loading conditions, when the exhaust velocity was 6m/s, it can better adapt to the drying operation in the drying room. When the exhaust velocity was 6m/s and the inclination angle of the guide plate was 15°, the combined air distribution can be more uniform. The CFD method was used to simulate the flow field inside the drying room, which enabled to know the specific distribution of the flow field inside the drying room intuitively and clearly, which had great advantages for the study of the distribution uniformity of the flow field in the drying room. Based on the results of numerical simulation, structural optimization and drying room renovation were carried out to reduce the cost of research and realize scientific and efficient technical application.