A long term follow-up for 42 cases of ulnar nerve repair was reported in this article, and the reason of bad function were analysed. They are: 1. As long as the injured ulnar nerve was sutured perfectly and without delay, the result would be satisfying. 2. The follow-up examination of the repaired nerve showed all the paralysed intrinsic muscles would recover in certain extent. Abductor digiti quinti, adductor pollicis and flexor digiti quinti brevis usually restored easily. Among the intrinsic muscles the best result of the first dorsal interosseous and the first palmar interosseous muscles were obtained. The functional recovery of the second and third palmar interosseous muscles usually was poor. 3. After repairing of the injured ulnar nerve, recovery of the claw hand deformity usually takes long time, so the operative correction of the deformity should not be performed until 2.5 years.