Objective To investigate the clinical efficacy of anchor repair combined with open reduction and internal fixation in treatment of ankle trimalleolar fracture with medial collateral ligament injury, and provide reference for clinical follow-up treatment. Methods Total 77 patients with ankle trimalleolar fracture and medial collateral ligament injury treated with anchor repair combined with open reduction and internal fixation in Department of Orthopaedics, Affiliated Hospital of Medical College of Ningbo University from April 2016 to December 2017 were selected. All patients were followed up for 1.5 years. The ankle function was evaluated by Baird standard. At the same time, the incidence of mechanical ankle instability and other related complications were observed. Results Total 77 cases of ankle trimalleolar fracture with medial collateral ligament injury were successfully treated with open reduction and internal fixation, and the functional recovery was satisfactory. The excellent and good rate of ankle joint function recovery after open reduction and internal fixation for traffic accident injury, sports injury and fall injury was 100.00%, 100.00% and 90.48%, respectively. There was no significant difference in the excellent and good rate of ankle joint function recovery among the three different injury factors (χ2=5.476, P=0.144). No complications such as mechanical ankle instability occurred during the 1.5-year follow-up. Conclusion Anchor repair combined with open reduction and internal fixation for ankle trimalleolar fracture with medial collateral ligament injury can effectively improve the flexibility and stability of ankle joint, and the recovery of ankle joint is good.