Presently the radiological examination is widely used for the assessment of in vivo bone condition. In some clinical problems such as diagnosis of the point of union of a fracture; the manual assessment is used along with radiological examination. Uncertainty regarding the significance of the radiographic and clinical findings may result in unnecessary long immobilization periods which can produce discomfort for the patient, as well as possible stiffness of the joints and sometimes permanent loss of mobility specially in older population. This paper deals with the in vivo analysis of bones by Acousto-Ultrasonic technique. The fracture was created through surgery on one of the limbs of rabbit and healing process was monitored through acousto-ultrasonic technique. A new index known as bone healing index was defined to calculate the end point of healing. In most of the cases, the bone healing index value was found to be 0.80, indicating that 80 % of the strength could only be restored at the completion of healing process.