Abstract: Spiral bevel gears are key components in mechanical transmission, and the processing of the fillet radius is an essential process. However, issues such as inaccuracies in establishing the on-machine measurement coordinate system and difficulties in matching the theoretical tooth surface machining path with the actual tooth surface can affect the machining precision of the fillet radius. A precision processing method for the fillet radius of spiral bevel gears driven by accurate tooth surface matching is proposed. Firstly, an iterative method is used to accurately establish the on-machine measurement coordinate system for the spiral bevel gear. Secondly, the measurement model is corrected to avoid measurement interference. Thirdly, precise matching of the theoretical tooth surface with the actual tooth surface is performed. Finally, experiments on the processing of the fillet radius are conducted. The experimental results show that, in machining a 0.5 mm tip fillet of a spiral bevel gear with an outer diameter of 200 mm, the proposed method achieves an improvement of 96 μm compared with the conventional method.