Objective: To evaluate the effect of autograft bone,allograft bone,calcium sulfate bone cement,and calcium phosphate bone cement on the repair of tibial plateau defect in rabbits.Methods: We used autograft bone,allograft bone,calcium sulfate bone cement,and calcium phosphate bone cement to repair tibial plateau defect in rabbits.Gross and histologic observations,X-ray examination,and biomechanical test were conducted at 1,2,4,8 weeks after operation.Results: X-ray examination found that the bone density was evidently reduced in calcium sulfate group at 8 weeks after operation; there were no marked changes in other groups.The maximal load measurements showed that autograft and allograft groups were greater than calcium sulfate and calcium phosphate groups at 1 and 2 weeks after operation.However at 4 and 8 weeks after operation,no significant difference was found among the four groups.In autograft and allograft groups,there was no significant difference in biomechanical intensity at 2,4,and 8 weeks,but it was significantly higher than that at 1 week.In calcium sulfate and calcium phosphate groups,the outcome was ranked in descending order as 1 week＜ 2 week＜ 4 week =8week.Histologic examination found a great amount of new bones at 8 week in both autograft and allograft groups.In calcium sulfate group,calcium sulfate was almost absorbed and there were numerous bone trabeculations.There was a large amount of unabsorbed calcium phosphate in calcium phosphate group.Conclusion: At 1-2 weeks postoperatively,the biomechanical intensity is higher in autograft and allograft groups than calcium sulfate and calcium phosphate groups,but after 4-8 weeks,there is no significant difference among groups.At 1-2 weeks,the biomechanical intensity in all groups is increased,but at 4-8 weeks,there is no significant increase.The rates of absorption and bone formation are quicker in calcium sulfate group than calcium phosphate group.