The strength of Cu²⁺,Pb²⁺ adsorbed by the tested soil colloids could be expressed by pH₅₀ value.The strength of Cu²⁺,Pb²⁺ adsorbed was in sequence of old manured loessal soil>dark cultivated loessal soil>yellow loessal soil>yellow cinamon soil.Cu²⁺,Pb²⁺ adsorption of the tested soil colloids mainly include specific adsorption,and n value was regarded as characteristic value of specific and electrostatic adsorption proportion.The proportion between specific and electrostatic adsorption was related to pH.The percentage of Cu²⁺,Pb²⁺ specific adsorption by the tested soil colloids showed the trend of yellow cinamon soil>old manured loessal soil>dark cultivated loessal soil>yellow loessal soil.At lower pH,adsorbed mechanism was mainly controlled by hydrolysis-complex reaction;at higher pH,it was controlled by hydrolysis-complex and precipitating adsorption.The sequence of Cu²⁺,Pb²⁺ intrinsic complex constant of different soil colloids was consistent in adsorbed strength.If the interaction of metal ions was considered,the adsorption of soil colloids to metal ion could be described through BDM equation. value was expressed as Cu²⁺,Pb²⁺ adsorbed strength by soil colloid,the larger the negative value was,the larger the specific adsorbed strength was.The negative value of in different soil colloids was consistent with the sequence of Cu²⁺,Pb²⁺ intrinsic complex constant and permanent charge density.