Osteonecrosis is a kind of common condition which affects severely health and life quality of human being . Without specific treatment 80% of clinically diagnosed cases will progress, and most will eventually require arthroplasty. The goal is therefore to diagnose and treat the condition in its earliest stage. Because the treatment of osteonecrosis is determined in large part by the stage of the disease, it is important to use a reliable and effective method of classification and staging. It is well known the treatment on early diagnosis. The traditional diagnosis methods for osteonecrosis are X-ray, CT, MRI and biopsy, which are defect in early diagnosis and side effect. Photoacoustic tomography is an emerging imaging technique with great potential for a wide range of animal tissues and organ imaging application. This new approach to medical imaging relies upon irradiating the tissue with low energy, nanosecond pulses of laser light at a wavelength in the visible or near-infrared (NIR). Broadband (～30MHz) ultrasonic thermoelastic waves are excited throughout the irradiated volume at optically absorbing subsurface features and propagate to the surface of the tissue. It is proposed and investigated to establish the feasibility of using photoacoustic tomography to detect the early osteonecrosis of human femoral head, and compared with X-ray photography. The osteonecrosis model of rabbit had been performed. On the other hand, the specimen of human femoral head complicated with necrosis had also been researched. The results show the subchondral osteolysis and local cortical bone destructed in animal model in the tenth week. The early osteonecrosis pathology of rabbit model was the same as human femoral head. The reconstructed photoacoustic images were identical with the scale and shape of the specimen. The images had satisfied contrast and resolution. The spatial resolution of the images reaches 0.3 mm. It is feasible that the technique of the photoacoustic tomography is used in the detection of early osteonecrosis. A new diagnosis method for the early stage osteonecrosis will be demonstrated.