Objective:To study the possibility of natural hydroxyapatite/chitosan composite on repairing bone defects. Methods:We developed a natural hydroxyapatite/chitosan composite that could be molded into any desired shape. The powder component consists of natural hydroxyapatite, which is epurated from bone of pigs. The liquid component consists of malic acid and chitosan. Operations were performed on the left tibias of 15 white rabbits to create two square bone defects. One of the defects was reconstructed with the composite, while the other was not repaired and used as a blank control. Three of the animals were killed at the end of 2 weeks, 4 weeks, 8 weeks, 12 weeks and 16 weeks respectively and implants were evaluated anatomically and histologically. Results:No apparent rejection reaction was found, except for a mild inflammatory infiltration observed 2 weeks after surgery. Fibrous tissue became thinner 2 ~8 weeks after surgery and bony connections were detected 12 weeks after surgery. The new bone was the same as the recipient bone by the 16th postoperative week. Conclusion:The hydroxyapatite/chitosan composite has good biocompatibility and osteoconduction. It is a potential repairing material for clinical application.