The invention relates the field of precision test technologies and instruments, and particularly relates to a contrast type anti-interference stepped plane reflector laser interferometer, a calibration method and a measurement method. The contrast type anti-interference stepped plane reflector laser interferometer comprises a laser source, a stepped plane reflector, an interference measurement photoelectric detector group, a movable plane reflector and a beam splitter group, wherein the laser source shots z laser beams to the beam splitter group, and the z is a positive integer which is greater than or equal to 2. The contrast type anti-interference stepped plane reflector laser interferometer is characterized by further comprising a reflection measurement photoelectric detector group. A second laser beam set shots to the beam splitter group from the movable plane reflector and then forms a reflected laser beam group, and each laser beam of the reflected laser beam group respectively shots to one reflection measurement photoelectric detector. The laser interferometer determines an interference state of a laser interference beam according to the intensity of the reflected laser beam group, thereby realizing a purpose of resisting environmental interference.