The invention discloses a laser radar for measuring atmospheric NO2 concentration based on the differential absorption method of a Raman light source, which includes a rotating Raman laser source, a light receiving and light splitting component, and a photoelectric detection and control processing part, and is characterized in that: the light receiving The light-receiving telescope tube receives the backscattered light from the atmosphere with the light-splitting part, and the incident fiber is coupled to guide the light into the focal plane of the lens, collimated by the lens and injected into the grating, and splits the light with two wavelengths of 354.71nm and 360.00nm After exiting, it is received by two outgoing optical fibers located at the focal plane of the lens; the grating is a blazed grating, which has a certain angle with the lens; the photoelectric detection and control processing part includes a microcomputer, a data acquisition card, a delay device, an amplifier Shaping circuit, photomultiplier tube and photoelectric probe. The invention has the beneficial effects of simple structure, low cost, high diffraction efficiency, good flexibility, convenient use and maintenance, and the like.