The damaged inferior alveolar nerve of rabbit was repaired with autogenous ipsilateral greater auricular nerve grafting primarily and secondarily, and electrophysiological, ultrastructural, microvascular and histochemical investigations were performed in this study. The results indicated that the experimental effects of group 1 out of 3 groups (group 1 with immediate grafting, group 2 with grafting after 4 weeks, and group 3 with grafting after 8 weeks) were the best and those of group 2 were second only to group 1 with no obvious difference between these two groups (P greater than 0.05). However, the results of group 3 were not good enough, and there was significant difference from the other two groups (P less than 0.05). Therefore, we were led to conclude that the injury should be repaired at once or within 4 weeks after inferior alveolar nerve was damaged, or within 2 or 3 months thereafter, to improve the function of the injured nerve as greatly as possible.