In order to improve the precision and efficiency of tooth profile error online measurement of automatic tracking measurement, based on the principle of measurement of the circular arc interpolation method, the adaptive tracking in the curvature of tooth profile error online measuring method was put forward. By measuring probe with different scanning velocity measured gears tooth surface, the three dimensional (3-D) coordinates were obtained, and then through the program calls MATLAB to deal with these coordinates, the involute cylindrical gear tooth profile deviation were obtained. The effects of different probe measurement rate on the result of error were compared, and on machine measurement were carried out to verify the effectiveness of this method. Results show that the method can make the distribution of collected data point reasonable, measurement point with high precision, and data processing easy to realize with high measuring efficiency. 