Abstract:Pinus koraiensis plantation in Changbai Mountain was regarded as research object in this paper.Spatial distribution and compositional evolution of soil cation exchange capacity(CEC) in Pinus koraiensis plantation were studied by the methods of comparison and analysis.The result showed that soil CEC and base saturation pencentage in Pinus koraiensis plantation decreased with the age going on,but the contents of exchangeable H+ and Al3+ were opposite.The contents of CEC,exchangeable Ca2++ and Mg2++ in the surface layer were higher than those in the bottom.The contents and composition of CEC in rhizosphere soil were more than those in non-rhizosphere soil.The contents of CEC,exchangeable Ca2++,Mg2++ and Na+ in Pinus koraiensis broad-leaf mixed forest were higher than those in the Pinus koraiensis plantation.