〔Abstract〕Objective To explore the application value of posterolateral approach for open reduction and internal fixation in the clinical treatment of ankle fractures and its influence on the complication rate. Methods A total of 60 patients with ankle fracture admitted to Lianjiang People's Hospital from October 2016 to April 2021 were selected divided into two groups, and according to the difference of treatment plan, 30 patients received posterolateral approach for open reduction and internal fixation (as the observation group), and 30 patients received reduction and plaster external fixation (as the control group). The excellent and good rate of treatment, recovery of ankle joint function and complication rate were analyzed and compared. Results The excellent and good treatment rate was higher in the observation group, and the weight-bearing walking time and fracture healing time in the observation group were shorter than those in the control group, and the hospitalization time in the observation group was longer than those in the control group, with statistical significance (P < 0.05). Before treatment, there was no significant difference in American Orthopaedic Foot and Ankle Society (AOFAS) score between the two groups (P > 0.05). After treatment, AOFAS scores of the two groups were improved, and the recovery of the observation group was better than that in the control group, the difference was statistically significant (P < 0.05). There was no significant difference in the incidence of complications between the two groups (P > 0.05). Conclusion Posterolateral approach open reduction and internal fixation in the treatment of ankle fractures can achieve significant curative effect, good fixation effect, fast postoperative recovery, promote the recovery of ankle function as soon as possible, and effectively control and prevent the occurrence of complications, with both efficacy and safety.