The invention discloses a method and a device for interference fringe automatic counting used for a Michelson interferometer. The method for interference fringe automatic counting used for the Michelson interferometer comprises initializing an interference fringe count value, enabling a photoelectric sensor to be aimed at an interference fringe, adjusting drum wheels of the Michelson interferometer, collecting analog voltage signals output by the photoelectric sensor at the same time, filtering and eliminating a 50 Hz artificial lighting device light source interference signal, converting the artificial lighting device light source interference signal into a digital voltage signal, converting the digital voltage signal into high electrical level or low electrical level, and adding one to the interference fringe count value and outputting the count value when converting from the high electrical level to the low electrical level is detected. The device for interference fringe automatic counting used for the Michelson interferometer comprises a mainframe box with a master control circuit board and a power supply circuit board, wherein a power switch, a power socket, a flexible metal tube, a push-button unit, a liquid crystal display and a power indicator light are arranged on the mainframe box, and a front-end amplifying circuit, a 50 Hz light source filter circuit, an analog-digital conversion circuit and a microprocessor are arranged on the master control circuit board. The method and the device for interference fringe automatic counting used for the Michelson interferometer have the advantages of being high in counting accuracy, strong in anti-interference performance, and high in counting efficiency.