Objective To investigate the operative technique and cl inical results of repairing the soft tissue defects of knee with antegrade extended peroneal artery perforator flap. Methods From October 2007 to January 2008, 3 patients (2 men and 1 woman) with the soft tissue defects of knee were treated, with the ages of 18, 31 and 42 years, respectively. The first casesustained femur and pelvis fractures and soft tissue defect over his right popl iteal fossa, which were treated with open reduction and internal fixation (ORIF) and debridement of knee joint 2 weeks ago. The second case was necrosis of skin 3 weeks after ORIF for fracture of tibial plateau. The third case suffered from open fracture of tibial plateau and soft tissue defect, which were treated with external fixation and debridement 3 weeks ago. The defect sizes were 16 cm × 9 cm, 11 cm × 6 cm and 14 cm × 7 cm. The flap was raised by dividing the peroneal artery and veins distally and elevating them proximally, which covered for the defects of knee. The flaps were designed with the size of 18 cm × 10 cm, 12 cm × 7 cm and 15 cm × 8 cm. The pure vascular pedicle of the flap was 10 cm to 17 cm in length, including the peroneal vessels and one or two perforator branches. The donor site is covered by a spl it thickness skin graft. Results All flaps survived after surgery. The donor sites healed by first intention and the skin grafts survived. After following up for 6, 8 and 11 months, the appearance and function of the flaps were all satisfactory. Based on the modified HSS knee performance system, post-operative knee functional outcomes of three patients were excellent. Conclusion The antegrade extended peroneal artery perforator flap suppl ied by a pure vascular pedicle can be a good alternative for reconstruction of knee. The flap, with a long and thin pure vascular pedicle, could provide good texture and contour matching the recipient area.