Since 1989, 17 cases ( 18 fingers) of mallet finger underwent surgical repair of the extensor tendons of the fingers combined with postoperative perpendicular pin transfixion. The follow-up was through 3 to 8 months. The results were 13 satisfactory, 4 improved and one failure. The method of pin transfixion was introduced in detail, and the classification of mallet fingers and the principles of treatment were discussed in detail, and the classification of mallet fingers and the principles of treatment were discussed.