The results on exchange-adsorption between aluminium and manganous ion in red soils were shown: These two ions expressed both chemical behaviours according to the universal rules of ion exchange and quite distinct characteristics of nonequivalent exchange. Nonequivalent exchange and its nonelectrical adsorption between aluminium and manganousion resulted from their hydrolysis nature, which were influenced by property of solid surface, relative exchange power of ion pair and ion amount added. The parameters concerned k, r, 1/n, K and ΔF were also explained. In view of ΔF, the processes which were spontaneous and irreversible towards stable state for exchange of manganous ion by aluminiun and adsorption of aluminium by red soil were demonstrated in thermodynamics.