Abstract: The toxic effects of environmental Cd²⁺ pollution on Sagittaria sagittifolia L.were mainly stu-died.It’s found that Cd²⁺ toxicity induced the roots different degree of browning,blackening and growth restriction.The ultrastructural damages of the leaf and root cells were mainly expressed in chloroplast swelled,thylakoids disordered,mitochondrial cristae decreased,mitochondria swelled and vacuoled as well as chromatin polymerized.The cell wall incrassated,cell shape twisted and cell arrange disordered in the scanning electron microscope.The energy spectrum analysis showed that with the environmental Cd²⁺ concentration increasing,the Cd²⁺ contents in a single root tip increased,and the absorption of other nutrients was affected to varying degrees.Cadmium toxicity on S.sagittifolia L.had clear dose-response and time effects.