The acidification characteristics and influencing factors of paddy soils profiles developed from typical parent materials in south China were clarified to provide theoretical basis for effective prevention and control of soil acidification in paddy fields.Hydragric paddy soil profiles developed from different parent materials(Plate shale，Quaternary red earth，Granite，River alluvial material，Sandstone，Limestone，Purple sand shale)were collected from Chang-Zhu-Tan area in Hunan province，the soil pH of plough layer(A)，below plough layer(P)，storage layer(W)and parent material layer(C)were measured，topsoil acidification was estimated by the difference in the soil pH between layers A and C，and the organic matter，cation exchange capacity，total nitrogen and particle composition were measured to study the main factors influencing the plough layer acidification.The results shoued that the acidification characteristics of hydragric paddy soils developed from southern typical parent materials were as follows: the pH of limestone soil profile was the highest，reaching 6.39 ～ 6.92，followed by the river alluvial material(6.24 ～ 6.66)and purple sand shale(5.90 ～ 6.57)，which were slightly acidic to neutral；thirdly，the plate shale soil(5.91 ～ 6.46)was slightly acidic；finally，the quaternary red earth(5.45 ～ 6.12)，granite(5.47 ～ 5.88)and sandstone soil(5.47 ～ 5.85)were successively acidic to slightly acidic.There were obvious differences in soil pH between layer A and C of hydragric paddy soils developed from different parent materials，and acidification occurred in all of them，with the degree of acidification were in order as follows: purple sand shale，quaternary red earth>plate shale，limestone，granite>river alluvial material and sandstone.The stepwise linear regression analysis of soil physiochemical properties that may affect the acidification of topsoil showed that the cation exchange capacity of soil was significantly negatively correlated with the difference of acidification of topsoil.The cationic exchange capacity of soil is the main factor affecting the surface acidification of hydragric paddy soil developed from different parent materials.