Abstract: As a common mangrove plant which grows naturally along the beach, pittosporum tree has a certain representation in the field of mangrove restoration.In this experiment, the tree seedlings transplanted from the river confluence reaches were planted in artificial sewages.The ionic concentrations inside are outperformed as follow: Cr⁶⁺2.5mg/L, 3.5mg/L, 5.3mg/L, Ni²⁺1.0 mg/L, 2.5mg/L, 5.0mg/L, Cu²⁺0.5 mg/L, 1.0mg/L, 2.0mg/L. The results showed that: trees planted under the ionic concentrations of Cr^{6 +}2.5 mg/L, Ni²⁺5.0 mg/L, Cu²⁺2.0 mg/L exhibited better purifying effects. The conterntrationt order of Cr^{6 +}, Ni²⁺, Cu²⁺ in the plants are: roots> leaves> stems. Compared to the other two elements, accumulation coefficient of Cu²⁺ in pittosporum trees was the highest. And Ni²⁺ comes follow. This experiment was set out to provide some references for future study of mangrove plants applying in rivers, lakes, wetland system.