Abstract: Based on an analysis of the particle size, chemical composition, heavy minerals, sporo-pollen assemblage, SEM photos of quartz paricles and characteristics of their distribution and structures and textures at some sections of the Xiashu loess along the lower reaches of the Yangzi River, it has been realized that the formation of the Xiashu Ioess has gone through a very complicated process and this process of formation can not be explained by a simple pattern of wind-blown accumulation or watercoursed accumulation. But the wind-blown accumulation is a primary and master factor of all the factors. The watercoursed accumulation is the second and auxilliary factor. The Xiashu loess was carried from the northwestern region of China by the wind-blown process.