Abstract: A new mobile lidar system with day and night capability has been developed for the application research of test engineering and environmental monitoring. The lidar system was composed of a horizontal measurement module and vertical measurement module, which can receive the Mie scattering and Raman scattering signal that come from the action of laser and aerosol particles, water vapor molecule, nitrogen in atmosphere. Atmospheric horizontal visibility, vertical aerosol extinction coefficient and water vapor mixing ratio can be retrieved. The lidar system can provide continuous observation day and night, the actual measurement results and comparison experiments show that the measurement error of atmospheric horizontal visibility is less than 10%, and the error of the vertical aerosol is below 10% under the height of 6 km, and the maximum error of water vapor is not exceeding 20%. The mobile lidar system can be provided to meet the various application requirements for atmospheric parameters measurement.