The invention provides a dispersion compensation device based on a diffraction lens. The problem that when light beams pass through an optical grating or a dispersion diffraction device similar to the optical grating at different diffraction levels or grating constants, light beam dispersion can not be compensated for at the same time is solved. The device is composed of an optical element (5), the diffraction lens (2), an achromatic agglutination lens set (3) and a microscope objective lens (4) which are sequentially connected through a light path. The device is high in practicability, can have a light path adjusting effect and a dispersion compensation effect at the same time, and can be used for compensating for scanning dispersion of an acousto-optic deflection device.