To investigate the effect of mechanical dynamic stretching combined with progressive target rehabilitation exercise on functional recovery of patients with pronation external rotation (PER) ankle fracture.Methods 94 patients with PER type III or IV ankle fractures treated in Nanjing Drum Tower Hospital from February 2017 to February 2021 were selected as the research objects. The control group was given progressive target rehabilitation exercise after operation, and the observation group was given mechanical power pulling on the basis of the treatment of control group. Statistical analysis was performed to compare the VAS scores, ankle dorsiflexion and plantar flexion angles, ankle swelling, AOFAS ankle-hindfoot score, quality of life score, and complication rate after surgery between the two groups.Results The VAS pain scores in the observation group at 3 and 6 months after operation were significantly lower than those in the control group (all P＜0.05). The ankle dorsiflexion and plantar flexion angles of the observation group were significantly higher than those of the control group at 2 weeks, 1 month, 3 months, and 6 months after operation (all P＜0.05). There was no significant difference in ankle swelling between the two groups of patients with ankle fractures before surgery at 2 weeks, 1 month, 3 months, and 6 months after surgery (P＞0.05). The excellent and good rate of the AOFAS ankle-hindfoot score in the observation group was 90.9% (40/44), which was significantly higher than the control group by 70.0% (35/50) (2=6.345, P=0.012). The AOFAS ankle-hindfoot scores of abnormal gait and anterior and posterior activities (flexion/extension) in the observation group were significantly higher than those in the control group (all P＜0.05). The various dimensions of quality of life such as material, psychological, social, physical in the observation group 6 months after surgery were significantly higher than those in the control group (all P＜0.05). There was no significant difference in the incidence of complications between the two groups (P＞0.05). Conclusion Mechanical power traction combined with progressive target rehabilitation exercisecan can reduce pain and improve ankle function in patients with PER type III or IV ankle fractures after operation