[Objective]To introduce the surgical technique and preliminary clinical results of percutaneous cannulated screw fixationof displaced posterior malleolar fractures under arthroscopic supervision. [Methods] From September 2019 to September 2022, 31 patientsreceived percutaneous cannulated screw fixation of displaced posterior malleolar fractures under arthroscopic supervision for ankle frac-tures. At the level of the medial malleolar tip, lateral and medial portals 1.5 cm apart Achilles tendon were established. The arthroscope wasintroduced through the lateral portal to reveal the distal tibial articular cartilage step formed by the proximal displacement of the posteriormalleolar fracture block. The posterior malleolar fracture block was reduced by percutaneous prying and fixed with cannulated screws un-der the surveillance of arthroscopy. [Results] All the 31 patients were operated on smoothly without complications of vascular and nerve in-jury, with the operative wounds healed in one stage, and fracture healing in (9.4±2.3) weeks on an average. Compared with those preopera-tively, VAS [(6.1±1.9), (0.7±1.9), P＜0.001], AOFAS [(38.2±11.7), (97.4±5.8), P＜0.001] and Maryland score [(52.7±17.1), (95.5±6.3), P＜0.001] were significantly improved by the time of the latest follow-up. Postoperative imaging showed that the articular arc was completelyrecovered or remained a step ＜2 mm in 28 cases, and a step ＞2 mm in 3 cases. [Conclusion] This technique has advantages of direct visionduring operation, accurate reduce and fixation, minimizing posterior soft tissue involvement, which is conducive to recovery of ankle jointfunction, and fracture healing.