[Objective] To investigate the clinical effect of posterior lateral combined posterior medial approach in the treatment of Haraguchi Ⅱ posterior malleolus fracture. [Methods] Retrospective analysis was performed on 29 cases of Haraguchi Ⅱ posterior malleolus fractures treated by open reduction and internal fixation (ORIF) through posterior external combined posterior medial approach from July 2017 to June 2020. All cases were closed fractures. The posterior malleolus was divided into posterior medial and posterior lateral fracture fragments, accompanied by medial and lateral malleolus fractures. The operative time, blood loss, fracture healing time, range of motion and surgical complications were recorded. The AOFAS ankle-hindfoot scale and visual analogue scale (VAS) of pain were used to evaluate the clinical effects. [Results]All patients received successful operation with operation time of (85.17?18.74)min on average (ranged 72 ~ 123 min) and intraoperative blood loss of (47.39?23.81)ml (ranged 30 ~80 ml). The follow up lasted for 15 to 34 months with an average of (20.12?3.49) months. The patients achieved fracture healing from 11 to 15 weeks with an average of (12.34?2.21) weeks postoperatively. As time went on after operation, the AOFAS ankle-hind foot scores significantly increased, whereas the VAS scores significantly decreased (P<0.05). At the latest follow up, no a statistically significant difference was proved in active ankle ROM between the affected and healthy sides (P>0.05), in addition, the clinical outcomes were graded as excellent in 26 patients, good in 2 and fair in 1, associated with the excellent and good rate of 96.55% based on AOFAS score, despite of the fact that 2 patients surfed from symptomatic traumatic arthritis, which subsided by modified daily life and NSAIDs drugs. [Conclusion] The ORIF through posterior external combined posterior medial approach for Haraguchi Ⅱ posterior malleolus fracture take benefits of sufficient exposure of the fracture, reduction and fixation, early functional exercise and good recovery.