Abstract: [Objective] To investigate the surgical technique and clinical effect of posterolateral combined with modified posteromedial approach in the treatment of Klammer Ⅲ posterior Pilon fracture. [Methods] 21 patients with Klammer type III posterior Pilon fracture treated in our hospital from January 2018 to April 2021 were retrospectively analyzed, including 12 males and 9 females, aged from 21 to 65 years, with an average age of (41.21 ± 1.90) years. All patients were treated with posterolateral combined with modified posteromedial approach incision. The operation time, intraoperative blood loss and wound complications were recorded. The reduction of ankle fracture was evaluated by ankle X-ray and CT. At the last follow-up, VAS was used to evaluate the postoperative ankle pain, and AOFAS was used to evaluate the ankle function. [results] 21 patients were followed up for 8 to 22 months, with an average of (15.20 ± 1.51) months; The operation time ranged from 70 min to 135 min, with an average of (101.00 ± 4.30) min; The amount of bleeding was 35 ml to 120 ml, with an average of (77.04 ± 6.52) ml. Postoperative ankle CT showed that 18 patients obtained anatomical reduction and 3 patients had articular surface displacement of 1mm to 2mm.One patient developed superficial wound infection after operation and healed smoothly after dressing change.The VAS of the last follow-up was 0 to 3, with an average of (1.85 ± 0.20). AOFAS was 71 to 95 points, with an average of (86.04 ± 1.43).[Conclusion] The posterolateral combined with modified posteromedial approach in prone position can fully expose the lateral column, medial column and posterior column. It is a safe and effective surgical method with convenient reduction, high reduction rate, safe incision and less complications.