Based on field investigation and laboratory analysis including grain size analysis, transmission electron microscopy (TEM), chemical composition and X ray diffraction (XRD), relationships between slope disintegration and rock soil characteristics of granite weathering mantle are discussed. The coarse grains take advantage in the mantle which have a loosen structure with lots of cranny, and its strength are influenced mightily by water. In general, there are 5 layers in typical granite weathering mantle...