In order to study the cloud microphysical properties, the data of Ka-band millimeter radar and microwave radiometer were used to retrieve the stratus cloud microphysical variables of a light rainfall process over Shouxian, Anhui province on Oct.29 2015. Both single-factor and double-factor methods were used for retrieval. The methodology was firstly introduced, and then the cloud microphysical variables were retrieved and comparatively analyzed. The result shows as that:(1) the stratus cloud droplet concentration was about 1000 cm^-3 before rainfall, and the effective radius was smaller than 4.5 micro-meters.(2)The stratus cloud droplet concentration turned to be significantly less, about 500 cm^-3 after rainfall, but the effective radius was slightly increased by 1 to 1.5 micro-meters.(3)Cloud liquid water content weakly increased after rainfall, no more than 0.1 g/m³. (4)Before rainfall, the cloud microphysical variables fluctuated significantly with height, but the tendency became smoothly after rainfall, which implied that the cloud was getting more stable dynamically.