Equal optical path position adjusting method of optical fiber point diffraction interferometer

An equal optical path position adjusting method of an optical fiber point diffraction interferometer relates to the technical field of optical measurement. The method can effectively judge whether reference light and testing light have the equal optical path or not and has a relatively low price. A polarization splitting prism, two polarization sheets, two coupling lenses and two optical fibers are additionally arranged behind a first polarization splitting prism; optical path conditions of the reference light and the testing light are reflected on an interference pattern and the optical path difference of the reference light and the testing light is judged by the contrast ratio of the interference pattern, which is a direct physical amount; an optical method, but not a mechanical method, is used for adjusting an equal optical path position, so that the optical path conditions of the reference light and the testing light are quantitatively given; the equal optical path position adjusting method has the advantages of high precision, high efficiency, simplicity in operation and the like.