Southern China suffered four severe freezing rain and snow storm processes during January 2008. In this paper, a classical freezing rain process during 25-29 January 2008 was selected as a research case. Characteristics of stratification structure and cloud physics of the freezing rain were analyzed. Combining with observation, the freezing rain process during 28-29 January 2008 was simulated by the CAMS (Chinese Academy of Meteorological Sciences) mesoscale cloud model. The authors studied characteristics of micro-macroscale structure of cloud system over the freezing rain area and initially analyzed the microphysical process in the cloud and the mechanism of freezing rain formation. The results show that, the stable and thicker melting layer and cold layer at low levels was direct cause that the wide range of freezing rain appeared. Two different types of clouds existed over different freezing rain areas in this freezing rain process. Two types of clouds have different characteristics of stratification structure and cloud physics and mechanism of freezing rain formation. Clouds over the Hunan Province freezing rain area belonged to mixed-phase cloud: the cloud thickness was deeper, the cloud top temperature was lower, and in the clouds there were large amount of ice-phase particles. Under the consideration of stratification ("cold-warm-cold" layer), the freezing rain over Hunan Province was formed by ice-crystal mechanisms (the melting process). That is, the freezing rain developed as the falling snow encounters a layer of warm air, and then the snow completely melted and became rain. As the rain continued to fall, it passed through a thin layer of cold air just above the surface, cooled to a temperature below freezing, and formed supercooled drops. When the supercooled raindrop dropped and struck the ground, or anything else below 0℃, they instantly freeze, forming the freezing rain. However, clouds over the Guizhou Province freezing rain area belonged to warm clouds: the cloud thickness was thinner, the cloud top temperature was higher, and in the clouds there were little ice-phase particles. Under the consideration of stratification ("warm-cold" layer), the freezing rain over Guizhou Province was formed by supercooled warm-rain processes (collision-coalescence process). Supercooled raindrops developed by microscopic cloud droplets collecting one another as they fall. Ice processes were not involved in the formation of these raindrops.