Objective:To investigate the treatment effect of using posterolateral approach under arthroscopic for senile ankle fractures.Methods: The clinical data from 30 cases of ankle fractures of the elder patients were received arthroscopic therapy (observation group) and 30 cases underwent surgical treatment(control group), both of the two groups were analyzed by retrospectively. The operation time, amount of bleeding and recovery time were compared between two groups. McGuire scoring standard was used to measure and compare the ankle function before and after surgery.Results: There were difference between two groups in the operation time, amount of bleeding and recovery time; and the observation group were less than control group in these indexes (t=26.82,t=23.54,t=31.21;P<0.05). Before surgery, there was no difference in term of McGuire scores between two groups. McGuire scores of every group after surgery was higher than those before surgery (t=12.34, P<0.05); and ankle function in observation group was improved more significantly than those in control group.Conclusion: Arthroscopic therapy could clearly find the joint injury, treatment in time, have little tissue damage and safety during operation, and it can improve the treatment effect.