Objective To compare the effect of two different operations on treating severely comminuted intercondylar fracture. Methods From December 2001 to October 2003, 20 cases of severely comminuted intercondylar fracture were operated. Of the 20 cases, 7(group 1) were treated with closed reduction and retrograde intramedullary nailing through arthroscope, 13(group2) were treated with open reduction and retrograde intramedullary nailing without arthroscope. Follow-ups were conducted after operation. Results All cases of fracture were recovered. Swelling in group 1 was alleviated more obviously than that in group 2. In group 1, all knees could flex to 120° during 6th to 9th weeks after the operation. In group 2, only 4 could flex 110°.Conclusion Retrograde intramedullary nailing through arthroscope proves to be less invasive and more effective in treating heavily comminuted intercondylar fracture.