Abstract: The relationship between speciation of heavy metals Cu,Zn,Pb and Cd and plants enrichment was researched.The results showed that the organic matter-sulfide bound and residuum speciation are the main content of Cu,Zn,Pb;the soluble and ion-exchangeable speciation(bioavailable speciation) is the main content of Cd,and so the ecological hazard of Cd is stronger.According to correlation analysis and partial correlation analysis,the content of heavy metals in plants directly correlates with the content of soluble and ion-exchangeable speciation of heavy metals in the existing environment of plants,which fits to the theory that the plants can only absorb the soluble speciation of heavy metals.The enrichment ability of plants in heavy metals is in the order of : Zn >Cu >Cd >Pb.It is more scientific to study plants enrichment by the soluble and ion-exchangeable speciation of heavy metals.