Cloud particle effective radius, cloud optical depth and other cloud parameters played an important role in the research of cloud microphysical characteristics and development of precipitation cloud. The study synthetically analyzed one precipitation process. The results showed that the cloud optical depth was larger in south and southwest area of Tianjin, the value were less than 50. The cloud particle effective radius was larger in south area of Tianjin, where the radar-reflectivity and vertical integration of liquid water were also larger. The cloud particle effective radius frequency chart presented bimodal distribution, while the cloud optical depth frequency chart presented unimodal distribution. The correlativity between precipitation and cloud particle effective radius, depth of super-cooled layer, cloud top height and cloud top temperature were well, and the optimized regression equation was reasonable and effective.