In southern China., there exist various lateritic soils such as ''Laterites'' (Hainan, Guangdong, Fujian and Yunnan Provinces), ''Lateritic clayey soils'' (Guizhou and Guangxi Provinces) and ''Lateritic silty soils'' (Hunan, Hubei and Jiangxi Provinces). In order to study the geotechnical properties of lateritic soils, the physicomechanical properties, chemical composition, mineralogical composition and microstructure features of samples of lateritic soils in China have systematically ayalysised by SEM, EDAX, XDA and conventional physico-chemical test. It has been found that the structural strength of lateritic soils come mainly from chemical bonds, residual or regenerated, between the particales from cementing forces of crystalline ferric oxides and from the influence of colloidal ferric hydroxide.