Abstract：Objective：To explore the effect of puerarin on chronic postoperative pain and its mechanism based on mTOR signal pathway. Methods： Fifty rats were randomly divided into control group， shamoperation group， model group， puerarin group and inhibitor group. The chronic pain model of skin/ muscle incision and retraction (SMIR) was used in rats. Puerarin group was injected intraperitoneally with puerarin [100 mg/(kg · d)] for 7 consecutive days， and inhibitor group was injected intraperitoneally with rapamycin [1 mg/(kg · d)] for 7 consecutive days，and the analgesic effect was observed. The change of pain threshold of rats in each group was detected by mechanical withdrawal threshold (MWT). The spinal cord samples of rats in each group on the seventh day were taken， and the protein levels of mTOR and p- mTOR in spinal cord tissue were detected by Western blot. Immunofluorescence staining was used to investigate the location of mTOR in spinal cord cells and observe the activation of microglia in the dorsal horn of the spinal cord. Results：Puerarin and rapamycin can alleviate the hyperalgesia caused by SMIR. Puerarin has no effect on the expression of mTOR in the spinal cord tissue， but reduces the protein expression level of p-mTOR in the spinal cord tissue. mTOR is co-located with microglia specific markers in the dorsal horn of the spinal cord. Puerarin and rapamycin can inhibit the activation of microglia in the spinal cord. Conclusion：Puerarin can alleviate the activation of microglia by inhibiting the phosphorylation of mTOR to treat chronic postoperative pain.