Clay minerals in soil affect soil physiochemical properties, indicate soil-forming factor characteristics, soil genesis process and intensity, and is important to distinguish mineralogy classes of soil family in Chinese Soil Taxonomy. In this paper, 18 soil profiles of Stagnic anthosols derived from different parent materials in different latitudes in Guangxi were investigated, clay mineral compositions and spatial distribution in hydragric horizon (Br) of each profile was analyzed by X-ray diffraction (XRD) and applied to distinguish mineralogy classes for soil family classification of clayed soil profiles. The results showed that: 1) clay minerals in Stagnic anthosols in Guangxi mainly consisted of kaolinite, illite, montmorillonite, gibbsite, vermiculite and 1.42 nm intergradient minerals. The percent of occurrence of kaolinite, illite, gibbsite, 1.42 nm intergradient minerals, montmorillonite and vermiculite were 100%, 88.9%, 72.2%, 61.1%, 44.4% and 38.9% respectively. 2) the composition of clay minerals has obvious regularity in latitude spatial distribution, with the increase of altitude, relative percentage of kaolinite decreased, while frequency of occurrence and relative percentage of illite, montmorillonite or 1.42 nm intergradient minerals increased. Parent materials obviously affected clay mineral composition in soils in the north area of 23°N latitude. 3) Latitude 23°N was dividing-line of clay mineral composition and mineralogy classes. In the south area of 23°N latitude, clay mineral composition in soils with different parent materials was dominated by kaolinite, mineralogy classes for the identification of soil families of clayed soil profiles was kaolinitic or kaolinitic mixed. In the north area of 23°N latitude, clay mineral composition dominated with kaolinite, montmorillonite, illite or 1.42 nm intergradient minerals, and mineralogy classes for the identification of soil families of clayed soil profiles included kaolinitic mixed, mixed or illitic.