Micro pulse lidar(MPL) is an effective tool for detecting atmospheric aerosol, cloud and mist, and visibility. It provides good stability and compact, convenient movement, accurate data and safe to eyes, etc. MPL’s principle and its two data processing methods including slope method and Fernald method are introduced. Its application in meteorology are also covered, including the following three aspects: the monitoring of horizontal visibility and foggy weather; the accurate detecting of the cloud information such as the height of cloud, the thickness of cloud layer, the extinction coefficient of cloud zone and the cloud layers; the vertical distinction of atmospheric aerosol and the spatial-temporal evolution of aerosol.