Temperature gradients were set at the opposite sides of the grain storage: 25°C-30°C, 20°C-30°C, 20°C-35°C, 30°C-30°C. The migration and distribution of imago of Sitophilus oryzae, Rhizopertha dominica and Tribolium castaneum in the grain storage were observed. The results showed significant differences that the distribution trends of imago of Sitophilus oryzae, Rhizopertha dominica and Tribolium castaneum within a certain grain storage temperature gradient (p < 0.05). The temperature gradient of grain storage is 25°C-30°C. Tribolium castaneum tends to gather in the 30°C side area of grain storage, while Sitophilus oryzae has no obvious trend, while Rhizopertha dominica tends to gather in the 25°C. The temperature gradient of grain storage is 20°C-30°C. Both Tribolium castaneum and Sitophilus oryzae tend to gather in the 30°C side area of grain storage, while Rhizopertha dominica tends to gather in the 20°C. The temperature gradient of grain storage is 20°C-35°C. Tribolium castaneum, Sitophilus oryzae and Rhizopertha dominica all tend to gather in the area on the side of grain storage at 35°C. The temperature gradient of grain storage is 30°C-30°C, and there is no obvious trend for Tribolium castaneum. Rhizopertha dominica tends to gather in the 30°C area on the left side of grain storage, while Sitophilus oryzae tends to gather in the 30°C area on the right side of grain storage. After cooling down, it was found that Sitophilus oryzae tended to gather in the center of the grain storage, while the Tribolium castaneum had no obvious trend, and the Rhizopertha dominica tended to gather in the peripheral area of the grain storage.