The loss of bone fragments, often due to trauma, infection, mass loss, or even complete bone regeneration after complicated fractures, is one of the constant challenges in medicine and veterinary medicine. Over the last decades, many efforts have been made to obtain materials that have the potential for high bone regeneration and to replace alternatives to autograft or zenografts. In this study, 45 adult male New Zealand male rabbits weighing 3-5 mg/kg, randomly divided into 3 groups of 15, were used. During surgery on the femur of each rabbit, a bilateral, 6 mm diameter defect was created. In the first group (control), no substance was used, in the second group, hydroxyapatite, and in the third group, nanocomposite tri-calcium phosphate (TCP) was used to fill the defect. Bone specimens were harvested for histopathologic evaluation on days 15, 30 and 45 and for evaluation of 4 indexes of union, spongiosa, cortex and bone marrow. The results showed that the results of using nanocomposite tricalcium phosphate in comparison with other groups were significantly different in all cases. Therefore, according to the results, it can be admitted that nanocomposite tri-calcium phosphate scaffold has a positive effect on the healing process and has good bone strength, so it can be widely used in orthopedic surgery as well as tissue engineering.