Gear mechanism is the most widely used transmission mechanism in modern machinery. Because of the high accuracy of gear transmission, the measurement of gear parameters is particularly important. When measuring the gear deviation by using the coordinate measuring machine(CMM), only a single item of deviation is measured. The process of measurement is complex and the efficiency of measurement is low. A fast method for measuring teeth profile parameters without the gear module of the CMM is presented in this paper. Taking the 3214M40F gear as an example, the data of teeth profile were obtained through accurate measurement of the profile of the gear. At the same time, two representative deviation items were selected from three aspects of motion accuracy, working stability and side gap: the radial runout and tooth profile deviation of the gear ring. The correct algorithm was determined according to the definition of deviation items. With the help of MATLAB and Origin, the gear profile was drawn and fitted according to the theoretical contour data of the gear measured by the CMM. The corresponding gear deviation was calculated. This paper provides a new method for measuring gear deviation, which is fast, accurate, simple and less manual intervention. The accuracy of the measurement was greatly improved.