The present paper deals with the effect of the components of paddy soils on the specific adsorption of copper ion and it's behavior.The samples used in present experiment were collected from Southern Jiangsu province,and they were obtained from the cultivated layers of paddy soils derived from lacustrine deposits with pH 6.2-6.8.Incubated samples were also used in this experiment.The methods and results of experiment are summarized as follows:1.The amount of specific adsorbed copper is the amount of fixed Cu⁺⁺ of soil which can not be replaced by NH₄⁺ ions but may be extracted by 0.1 N HCI.The Δ value of CEC,an ezpression of the specific adsorption sites in soil,is a reducing value of CEC of soil samples saturated previously with 1 N CuC_l2 before determining the CEC by routine method.The amount of specific adsorbed Cu⁺⁺ minus the Δ value of CEC is termed the "difference value" which is an another expression of specific adsorption sites in soils.2.The value of CEC was significantly correlated with free iron oxide and amorphous iron oxide (Table 3,Fig.1).The decrease in Δ valve of CEC of samples asa results of their deferrization showed a significant positive correlation with the amount of free iron oxide removed (Table 4,Fig.2).It is indicated that the free iron oxide may play an important role in the specific adsorption site which is expressed as the Δ value of CEC.In addition,the amount of adsorbed copper approached to the Δvalue of CEC when the matter was removed by H₂O₂ (Table 5).It gives another evidence for the conclusion mentioned above.3.In free iron oxide,amorphous iron oxide is thought to exert the most important effect on specific adsorption,because it is rnore active.It was confirmed by the result obtained from incubated samples that the Δ value of CEC increased with increasing activity of iron oxide,and there were highly significant correlations between them with a correlation coefficient of 0.865** (Fig.3).4.The "difference value" showed a significant correlation with organic carbon and complex-iron contents of the incubated samples (Table 4,Fig.4),in the natural paddy soils,there were no significant correlation between them.But there was highly significant correlation between the "difference value" and the amount of organic material remained in residue of deferrized samples (Table 4,Fig.6).On the other hand,the removal of organic material led to elimination of the "difference value" from the amount of adsorbed copper approximately (Table 5).These results further indicate that the organic matter is the another form of the carrier of specific adsorption of copper expressed as "difference value".