The tooth profile deviation of cycloidal gears is related to its transmission stability and motion accuracy. Based on image measurement technology,a non-contact detection method for tooth profile deviation detection of cycloidal gear is proposed,in order to solve the problem of low detection efficiency and lack of sample detection in the process of cycloidal gear detection. Based on the optical image measurement system and the Sobel edge detection algorithm,the complete tooth profile image and the actual tooth profile edge point coordinate of the cycloid gear are obtained. Based on the tooth profile equation of cycloid gear and the method of partition approximation,the theoretical coordinate value of the normal direction along the measuring point are obtained,and the tooth profile deviation solving model is established,and the measurement of the tooth profile deviation of the cycloid gear is realized,the factors causing the tooth profile deviation of the cycloid gears are analyzed,the basis for the design and manufacture of the cycloid gears is provided.