An embodiment of the present disclosure provides a spectrum inspecting apparatus. The apparatus includes a laser source; a focusing cylindrical lens configured to converge a light beam onto a sample; a light beam collecting device configured to collect a light beam signal, which is excited by the light beam, from the sample, so as to form a strip-shaped light spot; a slit configured to receive the collected light beam and couple it to downstream of a light path; a collimating device; a dispersing device configured to disperse the collected light beam so as to form a plurality of sub-beams having different wavelengths; an imaging device configured to image the sub-beams on the photon detector array respectively, wherein the light beam emitted from the laser source has a rectangular cross-section, the strip-shaped light spot impinges on the slit and its length is smaller than a length of the slit.