Abstract: By using the hourly GMS infrared imagery and conventional meteorological data, an analysis of the meso-convective cloud clusters in the Mei–yu front during the rainstorm period in the reaches of Yangtze and Huaihe Rivers in 1991 is made. It includes the basic characteristics of the meso-convective cloud clusters in the Mei–yu front (such as, source, life cycle, direction and velocity of their movements, and their types of genesis etc.). The importance of the environmental conditions, especially the interaction between the cloud systems of middle and low latitudes for the formation of the meso-convective cloud clusters is discussed. Finally, a cloud model and a conceptual model for the development of meso-convective cloud clusters in the Mei–yu front is given