Abstract: A Rayleigh-Raman-Mie lidar(RRML) was constructed to detect atmosphere temperature, aerosols and cirrus. The simulated signal was calculated using aerosol model and lidar system parameters, and the design method of the signal detection unit and optical receiver unit was based on the characteristic of the simulated signal. By using the extremely sensitive R4632 photomultiplier tube and the photon counting system, the lidar system achieved higher signal to noise ratios of Raman and Rayleigh signals. By using the PMT gating control unit and the optical signal attenuating mirror, the system could detect signals backscattered by aerosols and cirrus linearly. Finally, the signal detected by the RRML system was given, which proves the rationality of the RRML design method.