The mobility, bioavailability and toxicity of soil metals are most likely controlled by sorption-desorption reactions.A better understanding of the sorption-desorption processes and mechanisms is crucial for assessment and remediation of heavy metal polluted soils, and for prediction of the metal sorption capacity of soils.Laboratory batch experiments were carried out to study Cd sorption by four representing soils from Yangtze River Delta in China.The thermodynamic parameters including K°, ΔG°, ΔH° and ΔS° were calculated by using sorption data for two different temperatures 25±0.5℃ and 35±0.5℃.Results showed that Cd sorption can be well described by Freundlich model.The sorption K f values decreased in the order: Lithic Ochri-Aquic Cambosols (238.8 dm³kg^-1) > Endogleyic Fe-accumulic Stagnic Anthrosols (115.4 dm³kg^-1) > Typic Gleyic Stagnic Anthrosols (54.40 dm³kg^-1) > Fe-accumulic Gleyic Stagnic Anthrosols (10.74 dm³kg^-1).The Cd sorption capacity of Lithic Ochri-Aquic Cambosols was 24 times as much as that of Fe-accumulic Gleyic Stagnic Anthrosols.The Cd sorption capacity of soils decreased after removal of organic matter.For four tested soils, Cd sorption increased with solution pH.The K° and ΔS° values increased with temperature, while ΔG° values decreased with temperature.The negative values of ΔG° suggested that Cd sorption was a spontaneous process.The positive ΔH° values indicated that Cd sorption was an endothermic process for four tested soils.