Aiming at the problem of uneven distribution of the commonly used spline fitting method for the spiral bevel gear processed by the knife pouring method, which affects the accuracy of the tooth surface contact simulation analysis, the method of realizing adaptive tooth surface partition reconstruction was proposed according to the vertex weight coefficient of the tooth surface control. The tooth surface partition was realized by the Newton-Raphson method to determine the tooth face theory control vertex. Based on the calculation method of the double quadratic NURBS surface weight coefficient, the weight distribution of the tooth surface control vertex was obtained, and the reconstruction of the tooth surface was realized by determining the optimal number of interpolation nodes in each region according to the control vertex weight coefficient. Taking the tooth surface of spiral bevel gear small gear machined by knife pouring method as an example, the tooth surface reconstruction side based on weight control was compared with the CATIA-based spline reconstruction and the Splinebased interpolation method reconstruction. The results showed that the tooth surface error of the tooth surface reconstructed by CATIA was random, the average error of the tooth surface was 2. 62 μm, and the error sensitivity of the tooth length direction was greater, resulting in spot ambiguity in the contact simulation analysis. By using the method of Spline interpolation reconstruction, the local area of the tooth surface appeared "overfitting", the error sensitivity of the tooth height direction was greater, and the average error of the tooth surface was 1. 94 μm, resulting in abnormal contact spots in the local area. By using the method of surface fitting with the adaptive distribution of the number of interpolation nodes with controlled vertex weights, the overall tooth surface error was uniformly distributed with a mean value of 0. 79 μm and the instantaneous contact spots were unique, providing a reliable guarantee for the correction of the gear contact area.