Mangshan is a granitic mountainous region which is located at 24°54'-25°03' north latitude and 112°43'-113°20' east longitude. The altitude of the highest mountain peak is 1902 meters. The examined soil samples were collected fron different altitudes. The layer-silicate minerals and the oxides of clay-size minerals of fifteen soil samples in five soil profiles on the north slop of the Mangshan Mountains in Hunan Province were studied by X-ray dif fraction analysis and chemical selective solvent extraction analysis respectively.