A high spectral resolution lidar(HSRL) based on injection-seeded laser and iodine absorption filter has been developed. The basic principle, data processing method and configuration of HSRL were introduced. The HSRL measurement of atmospheric transmission in cloud and dust cases were presented,and compared with the results retrieved by the traditional Fernald method. Due to the nonidentity in physical and optical properties of different aerosols and cloud, the lidar ratio assumed in Fernald method cannot agrees well with the real atmosphere and produces considerable error in atmospheric transmission. Utilizing different spectral width of molecular scattering and particle scattering, the HSRL could separate two kinds of signals with iodine filter. Therefore, HSRL can measure the atmospheric transmission quantitatively without the additional assumption of lidar ratio.