Taking the water of Changjiang River and the organic composition of Cynodon dactylon system as the research object,the enrichment migration situations of Cr (Ⅵ) in Cynodon dactylon were studied by dynamic simulation test. The studies showed that Cynodon dactylon can grow and develop at the initial concentration of Cr (Ⅵ) was 5. 0 mg / L and below. When the initial concentration of Cr (Ⅵ) reach 10. 0 mg / L,apparent poisoning was shown in Cynodon dactylon and it grew slowly. With the increasing of Cr (Ⅵ) mass concentration gradually,the amount of migration increased gradually. And the concentration of Cr (Ⅵ) in river was obviously reduced.