Cirrus has the effect of radiative forcing which is influenced by the microphysical properties of cirrus. An algorithm for retrieving the microphysical properties of cirrus based on micro-pulse lidar and millimeter wave radar is presented. In the algorithm, lidar extinction coefficient retrieved from backscatter signal intensity and water equivalent radar reflectivity factor are combined to obtain cirrus-cloud ice water content (IWC) and general effective size (GES). A cirrus case in Shouxian is analyzed using the proposed algorithm and the data from micro-pulse lidar and millimeter wave radar. The results show that the IWC and GES are 10-3~10-1 g/m3 and 1~200 μm, respectively, which are consistent with the empirical values. The changes of IWC and GES with time are in accordance with the evolutions of cirrus. The analysis results imply the feasibility of retrieving microphysical properties of cirrus from micro-pulse lidar and millimeter wave radar data.