Abstract: Spinosad that has the advantages of high insecticidal efficiency, safety to non-target organisms, and low residue is a secondary metabolite produced by Saccharopolyspora spinosa. It is an effective insecticide to control stored grain pests. At present, the application of spinosad in warehouse mainly adopts the process of insecticide mixed with surface grain (mixed process), but it is time-consuming and labor-intensive. Therefore, the application of spinosad is restricted in warehouse. In order to speed up the simple and efficient application of spinosad in warehouse, this work studied the spraying process of spinosad powder in warehouse based on the vacuum ventilation (spraying process) by analyzing the ventilation parameters, the homogenization and penetration depth of spinosad in warehouse, and the mortality of four kinds of main stored grain pests (Cryptolestes pusillus, Rhyzopertha dominica, Sitophilus zeamais and Tribolium castaneum). The results showed that the average wind speed of the fan was 7.57m/s, and the whole warehouse with a storage capacity of 1329 tons could be sprayed by spinosad within 30 minutes using spraying process. The total dosage of spinosad was 30 kg. The weights of spinosad powder in the disks near the insecticide spray points (A, G and K) were higher than the others. Otherwise, the spinosad powder was evenly distributed elsewhere on the surface. Compared to the mixed process, the penetration depth of spinosad using spraying process can be generally up to 45 cm and even reached 105 cm, which indicated that the spraying process was easier to penetrate grain pile for spinosad powder. At 7 days, the corrected mortality of four kinds of pests in the warehouse using spraying process was lower than that of mixed process. However, the corrected mortality of Sitophilus zeamais and Tribolium castaneum, higher than 89.5%, had no significant difference between the two warehouses using mixed process and spraying process at 21 days. In order to further optimize the application process based on vacuum ventilation and improve the homogenization distribution of the spinosad in horizontal and vertical planes, factors such as fan power, insecticide spray point setting, ambient temperature and humidity, and the size of warehouse should be taken into account. Since the advantages of simple operation, low labor cost and promising effect of pest control, it is feasible to apply spinosad by vacuum ventilation. This study laid a foundation for further application of spinosad in warehouse to control stored grain pests.