Three types of Point of Zero Charge (PZC), i. e. ck-PZC (Without B), ads-PZC(B adsorp tion) and des-PZC(B desorption), were measured in brown-red soil, yellow-brown soil and calcareous alluvial soil collected from Hubei Province. The ads-PZC, compared with its ck-PZC, decreased by 0.9 pH unit for the brown-red soil, and only by 0.3 pH unit for the yellow brown soil, but the corresponding adsorbed H⁺ (the potential ion) increased by 3.3 cmol kg^-1 and 3.5 cmol kg^-1, respectively. Therefore, if specific adsorption of B occurred, the buffering capacity of the yellow-brown soil for environmental acid was higher than that of the brown-red soil. The ads-PZC of the calcareous alluvial soil was nearly equal to its ck-PZC, and its adsorbed H⁺ varied within 1.0 cmol kg^-1. Most of the potential ion in electrolyte did not react with surface funct ional groups of soil colloid, but with calcium carbonate. Though the change in des-PZC to ads-PZC was small, the calcareous alluvial soil retained strong trend to adsorb H⁺ at B desorption. The amount of adsorbed H⁺ was two folds as much as that in the brown-red soil or the yellow brown soil, which suggested that the accelerat ing effect of adsorbed B on H⁺ adsorption by the calcareous alluvial soil just appeared at that time. The amount of B adsorbed changed with pH variation, which is connected with surface characteristics of soil colloids and B types. In lower pH range, net negative charge of soil surface was small, but B could combine with positiveion as ion pair, which was adsorbed on soil surface. The result also showed that the adsorption of B caused a ten fold increase of the adsorption of proton in acid soils.