Abstract: Arsenic(As) pollution is a ubiquitous environment problem in Shimen realgar mine area, Hunan Province, China. Huangshui Creek is especially polluted by the historical realgar mine for a long time. This study investigated the fates and flux of As in water, the spectroscopic characteristics and dynamic dissolution of As in the sediments, and bacteria diversity of sediments. The geochemical migrations of As in the creak and ecological risk of its sediments were investigated in order to help future comprehensive treatment of As pollution in the creek. The research showed that:(1) The total As in water was in the range of 0.28-10.43 mg/L, As(Ⅴ) was the main inorganic As species, and As(Ⅲ) was detected by LC-AFS. (2) Based on the calculation, the annual flux of the total As increased about 5.71 t in this area. (3) The obvious ATR-FTIR bands were observed at 463, 875 and 910 cm^-1, which were attributed to AsO₄^3-. The other bands occurring at 775 and 796 cm^-1 were attributed to AsO₃^3-. These results revealed that the sediment contained arsenic-bearing minerals. (4) Both As(Ⅴ) and As(Ⅲ) species were observed in the dynamic dissolution experiments of the sediments, the concentrations reached 0.014-0.550 and 0.002-0.291 mg/L after 6 h, respectively. (5) The 16S rRNA gene sequencing in the sediments revealed that aquatic ecology of the creek was affected by the As pollution, which results in the decrease of abundance and diversity of bacteria community, and the increase of some unidentified genus. In addition, the Proteobacteria and Bacteroidetes were the dominant phyla. In Conclusion, the As pollution of Huangshui Creek mainly originates from the arsenic-containing minerals in the creek channel, which dissolve and release arsenic into the water system. The adsorbed As in the sediment is unstable and it has potential risk to release again which may become a source of As contamination.