【Abstract】Objective: To explore the effect of arthroscopic surgery on patients with medial meniscus injury based on three-dimensional gait characteristics. Methods: A retrospective study was conducted on 17 patients with medial meniscus injury who were admitted to the Department of Joint Surgery from May 2019 to May 2020 as the observation group, and recruited 17 healthy persons with normal physical examination during the same period as the control group. Observe and compare the three-dimensional gait data of the two groups of patients through the three-dimensional gait feature analysis system. Results: (1) The preoperative step length and pace of the observation group were significantly different from those of the control group (P<0.05); (2) On the coronal surface, the adduction angle and adduction abduction ROM of the knees of the observation group were more than those of the control group Significantly decreased in the group (P<0.05); the postoperative adduction angle and adduction abduction of the observation group patients were significantly improved compared with those before the operation, but still did not reach the normal range (P<0.05). On the sagittal plane, the maximum bending angle of the swing phase, the maximum extension angle of the support phase, the maximum bending angle of the supporting phase, and the flexion and extension ROM of the observation group were significantly lower than those of the control group (P<0.05). The maximum extension angle, the maximum bending angle in the weight-bearing period, and the flexion and extension ROM were significantly improved (P<0.05), but compared with the control group, the maximum bending angle of the swing phase and the flexion and extension ROM were still significantly reduced (P<0.05); (3) The first and second peaks of flexion torque and adduction torque of the observation group were significantly lower than those of the control group (P<0.05), and the second peak of the adduction torque of the observation group were significantly higher than that before the operation (P<0.05) . Conclusion: After arthroscopic surgery for patients with medial meniscus injury, although the three-dimensional gait parameters have recovered to a certain extent compared with before surgery, they still have not fully reached the normal level, so targeted rehabilitation training after surgery is particularly important.