The invention discloses an automatic counting system of an interference ring, comprising an optical imaging module of the interference ring, an image signal acquisition and conversion module, a data collection and transmission module and a microcomputer data processing module, wherein the optical imaging module utilizes a Michelson interferometer to form interference stripes and images the interference stripes on a purpose-made light screen; the image signal acquisition and conversion module utilizes a line array CCD sensor to convert an optical signal of the interference ring into an electric signal; the data collection and transmission module converts the electric signal from the CCD sensor into a digital signal; the microcomputer data processing module receives and processes the digital signal from the data collection and transmission module and processes the digital signal; and the microcomputer data processing module carries out digital filtering and waveform image display on thedigital signal, automatically acquires the effective reference point of an image pixel, judges the change of the interference ring according to the change of the gradient of the effective reference point and the comparison of the gray-scale value and the threshold value of the pixel point corresponding to the center of the interference ring, and realizes the automatic counting of the interferencering. The invention has convenient control and measurement and high measurement accuracy.