This paper discusses the composition of minerals and their formation mechanism of two types of the lateritic weathering crust on Early Pleistocene basalts in the northern part of Hainan Island. At first, the mineralogy of various weathering zones is described. Then, three main physicochemical processes in microscopic range (replacement as pseudomorph, dissolution and illuviation) and the effect of hydrodynamic conditions in the same range on these processes are inferred on the basis of the study of microfabric characters of the weathered rocks. Finally, weathered sequence of minerals in the lateritic processes of basalts is proposed. This paper discusses the composition of minerals and their formation mechanism of two types of the lateritic weathering crust on Early Pleistocene basalts in the northern part of Hainan Island. At first, the mineralogy of various weathering zones is described. Then, three main physicochemical processes in microscopic range (replacement as pseudomorph, dissolution and illuviation) and the effect of hydrodynamic conditions in the same range on these processes are inferred on the basis of the study of microfabric characters of the weathered rocks. Finally, weathered sequence of minerals in the lateritic processes of basalts is proposed.