Abstract: Dredging is widely used as a measure to control water pollution and eutrophication. Taking the treatment project of a small and medium-sized river in Suzhou as an example, this study investigated the atmospheric environmental impact of dredging sediment. The pollution situation of the river sediment, as well as the concentration of hydrogen sulfide, ammonia, and odor at different time in the sediment yards were sampled and analyzed after dredging. The results showed that the concentration of hydrogen sulfide and odor at the boundary of the sediment storage yards remained basically unchanged, during the sediment discharge period.The concentration of ammonia had increased. The attenuation of the ammonia concentration was not significant within 100 meters in the downwind of the sediment storage yards boundary. After the sediment storage yards were leveled and the vegetation was restored,the ammonia concentration was reduced. The odor concentration at the boundary of the sediment storage yards met the relevant standard limits both in the period of sediment discharge and after vegetation restoration