Phyllosilicate minerals and aluminum (Al) oxides are the main sources of Al activation in the soil acidification process and they are also active parts of soil chemical reactions. 【Objective】 The phyllosilicate minerals in soils are usually tightly bound to Al oxides and organic matter. Therefore, Al mobilization during soil acidification should be affected by soil organic matter and Al oxides. However, the effect and mechanism of Al oxides on the activation of Al during phyllosilicate minerals and soil acidification are not well understood. 【Method】 Since the mobilization of Al is very sensitive to changes in system pH, the pH of mineral and soil suspensions was precisely controlled by constant pH automatic potentiometric titrator in this study, and the effects of gibbsite on kaolinite and amorphous Al(OH)₃ on Al mobilization during kaolinite and montmorillonite acidification were studied. In addition, the Al activation kinetics of two Al oxides and two phyllosilicate minerals at different pH were studied. Finally, a red soil developed from quaternary red clay was treated with Al coating, and the effect of Al coating on soil Al activation was studied. 【Result】 Al coating treatment did not change the d values of the diffraction peaks for kaolinite and montmorillonite. However, the intensity of the diffraction peaks for the two minerals decreased. This can be attributed to the physical masking of Al oxides on the kaolinite and montmorillonite. The results showed that the gibbsite can promote the mobilization of Al during kaolinite acidification. The Al coating can inhibit the production of exchangeable Al and promote the activation of soluble Al during kaolinite acidification. For montmorillonite, amorphous Al(OH)₃ was found to promote the production of exchangeable Al. The Elovich equation and the zero-order kinetic equation were used to fit the kinetic data, respectively. The results of Al mobilization kinetics of the four minerals showed that the release rate of Al followed the order: amorphous Al(OH)₃ > montmorillonite > kaolinite > gibbsite. The releasing order of Al from montmorillonite, kaolinite and gibbsite was consistent with their weathering sequence. After red soil was treated with Al coating, the contents of exchangeable Al and soluble Al in the soil increased significantly when the soil was acidified to pH 4.3, and the increase of soluble Al was greater than that of exchangeable Al. This is consistent with the result of Al-coated kaolinite, mainly because the main clay mineral in the soil was kaolinite. The increase in exchangeable Al was mainly because some hydromica and vermiculite were also present in the soil.【Conclusion】 Therefore, Al oxides showed different effects on the mobilization of Al from different phyllosilicate minerals, which was mainly related to the nature of the minerals (e.g., 1:1 or 2:1 phyllosilicate minerals) . The influence of Al oxides on Al mobilization in soils during soil acidification was mainly related to the type and content of clay minerals contained in the soils. The results of this study can provide evidence for elucidating the activation mechanism of soil Al and a reference for the inhibition of soil Al mobilization during soil acidification.