Sixty-four rabbits were used in this study, experimental bone defects were made in notch of the mandibular bone angle. Dan sheng was used in experimental groups. A pieces of bone at the edge of the defect was taken and observed by electron microscope in different period. The results were as follows: 1. The amount of osteoblast increase clearly. 2. The synthesis of protein was vigorous in fibroblast appeared as nuclear depression, nucleoli locating at one side and formation of endoplasmic reticulum bubble. as Therefore, we think that dan shen would take a role of improving the mandibular bone fracture healing.