The invention discloses a vibration-rotational Raman-Mie scattering multi-wavelength laser radar system and a working method thereof. The system comprises a first system and a second system, wherein the first system works in an ultraviolet wave segment, the second system works in a visible infrared wave segment, and the first system and the second system both comprise laser emission units, optical receiving units, signal detection and data collecting units and control units. The laser emission units are used for emitting lasers to air, the optical receiving units are used for receiving back scattering echo signals of the air on the lasers emitted by the laser emission units, and conduct rotational Raman, vibration Raman and elastic scattering light splitting on the back scattering echo signals, the signal detection and data collecting units are used for obtaining parameter information of air temperature, water vapor, aerosol and cloud from the back scattering echo signals after light splitting, and the control units are used for controlling the laser emission units, the optical receiving units and the signal detection and data collecting units to run. The vibration-rotational Raman-Mie scattering multi-wavelength laser radar system and the working method of the system can achieve all-weather air comprehensive continuous automatic observation.