Objective To investigate the effect of the ultrasonic osteotome in mandibular angle osteotomy. Methods Thirty-five cases who received simple mandibular angle osteotomy and regular reexamination were selected. Ultrasonic osteotome and bone knife handle were used cooperatively during the surgery. Results All 35 cases were followed up for 6 months to 5 years. Review of oral panorama film showed mandibular bilateral symmetry, smooth tnandibnlar margin, clear and complete mandibular nerve tube. Unilateral facial hematoma was observed in 1 patient. And the patient was recovered after 2 weeks of hematoma puncture and physical therapy. Conclusion Good results can be achieved in mandibular angle osteotomy by using ultrasonic osteotome.