To investigate the chemical combination forms of soil aluminum and its variation in different soil profiles, parent materials, characteristic soil layers and soil types, this study selected layered soil samples from 12 typical soil profiles of 4 parent materials developed in different regions of Hunan Province as the experimental material. The results indicated the mass fractions of exchanged aluminum(Ex-Al), adsorbed inorganic hydroxy aluminum(Hy-Al), organic complex aluminum(Or-Al), iron oxide-bound aluminum(DCB-Al), interlayer aluminum(In-Al), amorphous aluminosilicate and gibbsite(Nc-Al), mineral aluminum(Min-Al), and total aluminum(Alt) in the test soil were (0.31±0.24), (1.57±0.80), (7.24±4.77), (2.47±1.72), (5.10±2.85), (18.91±7.91), (126.78±18.49), (162.37±24.86) g/kg in the topsoil layer, (0.26±0.18), (1.24±0.89), (4.17±3.09), (3.24±2.69), (6.09±2.97), (23.81±10.68), (122.13±40.12), (160.91±51.39) g/kg in the lower layer of the surface, (0.16±0.16), (1.09±0.92), (2.93±2.46), (2.61±2.67), (5.49±3.12), (21.81±9.94), (137.44±27.01), (171.53±32.79) g/kg in the matrix layer, respectively. On the soil profile, the mass fractions of Ex-Al, Hy-Al and Or-Al gradually decreased with the increase of soil depth, while the mass fractions of DCB-Al, In-Al and Nc-Al increased firstly and then decreased. Among the 4 types of parent materials, the Ex-Al mass fraction in the topsoil layer was the highest in the quaternary red soil, while those in the subsurface layer and the parent material layer were the highest in the granite weathered soil; the mass fractions of Hy-Al and In-Al were the highest in the granite weathered soil; the mass fractions of Or-Al and DCB-Al were the highest in the limestone weathered soil; the Nc-Al mass fraction in the topsoil layer and the subsurface layer were the highest in the limestone weathered soil, while that in the parent layer was the highest in the granite weathered soil. Among the 6 characteristic soil layers, the mass fractions of Ex-Al, DCB-Al, In-Al and Nc-Al were the highest in the low-activity iron-rich layer, while the mass fractions of Hy-Al and Or-Al were the highest in the humus surface layer. Among the 4 soil types, the Ex-Al, DCB-Al, In-Al and Nc-Al mass fractions of the iron-rich soil were the highest, and the Hy-Al and Or-Al mass fractions of the newly formed soil were the highest. The main factors affecting the chemical binding form and distribution of aluminum in the soil were pH, organic matter, CEC, free iron, total aluminum and clay particles.