The invention discloses a prediction and real-time rendering system for mandibular angle osteotomy, which comprises a calibration subsystem, a prediction subsystem and a rendering subsystem, and is characterized in that the calibration subsystem is used for obtaining a lower dentition rivet point and a danger area of a mandibular angle osteotomy patient according to a preoperative CT image of themandibular angle osteotomy patient and calibrating a maximum osteotomy range; wherein the prediction subsystem is used for inputting a preoperative CT image, a preoperative photo, a prediction postoperative photo and a maximum osteotomy range of a mandibular angle osteotomy patient, into an osteotomy surface prediction model and predicting an actual patient's cutting line and an osteotomy surface,and the rendering subsystem is used for rendering the surgical field cutting line, the osteotomy surface and a danger area in real time in combination with AR equipment. According to the pre-operation CT, the pre-operation picture and the osteotomy surface prediction model of the actual patient, the operation field of the actual patient is rendered in real time, the operation precision is improved, the operation risk is reduced, the operation time is shortened, and operation complications are reduced.