[Aim]  To clarify the influence of temperature on the effectiveness of phosphine (PH₃) fumigation for the control of stored grain pests. [Methods]  Two main stored grain pests, Cryptolestes ferrugineus and Tribolium castaneum, were chosen as the research subjects. The eggs, larvae, pupae and adults of these two species were exposed to 400 mL/m³ PH₃ for 12, 24, 36, and 48 h at 20, 25 and 30 ℃, after which mortality was assessed. [Results]  Mortality of T. castaneum larvae, pupae and adults at 25 and 30 ℃ was significantly higher than at 20 ℃ (P<0.05). The duration of fumigation required to kill all developmental stages of C. ferrugineus was significantly less at 25 ℃ than at 20 ℃ (P<0.05). The highest mortality of all developmental stages of  C. ferrugineus and T. castaneum was observed at 30 ℃. At 30 ℃, 100% mortality was achieved in 48 h. In addition, fumigation duration significantly affected the mortality rates of all instars of both C. ferrugineus and T. castaneum (P<0.05). Under the same temperature, extending the fumigation duration enhanced the killing effect of PH₃ on the both pests (P<0.05), achieving 100% mortality after 48 h. [Conclusion]  Temperature, duration, and their interaction significantly influenced the mortality rates of all instars of both C. ferrugineus and T. castaneum. The mortality rates of both pests increased significantly with rising temperature.