Objective In early stage of femoral head osteonecrosis, bone grafting in necrosis region are used to prevent collapse. This paper studied the influence on mechanical ability of bone defects in human femoral head’s weight bearing region and the restoration degree of mechanical ability after being planted by different structural bone. Methods Four normal proximal femur of human were harvested. Bone defects (20 mm in diameter and 30mm in depth) within the femoral heads’ principal weight-bearing region were drilled and the biomechanical properties of both the intact and the defected proximal femur were tested in vitro by simulating single-leg stance phase. Rigidity of the whole proximal femur and the strain value at the juncture of femoral head and neck under 1400N load were evaluated. And then, the bone defects were implanted with three different structural bone graftings. Group I was femoral head block allograft. Group II was femoral condyle block allograft. Group III was impacted with cancellous bone chips. The rigidity and the strain value were recorded same as above. Results Compared with the intact group, the strain of the top junction of femoral head and neck in defect group increased 93.0% and the strain of the bottom junction increased 203.4%. After implanted with different structural grafts and compared with the intact group, the strain of top conjunction of femoral head and neck increased 6.6% in group I, 33.7% in group II and 150.4% in group III,respectively, while the strain of bottom conjunction increased 67.6%, 136.9% and 206.1%. Conclusion Bone defects of the weight-bearing region in human femoral head would increase the strain distribution around the conjunction of femoral head and neck. The change of strain value would be found obviously in the top and bottom conjunction. After implanted with femoral head block allograft, the stress concentration could be lessened. However, there is no obvious improvement in biomechanical properties after implantedwith cancellous bone chips.