Abstract: In order to investigate the effect of fluoride on ecological toxicity of Cipangopaludina cahayensis, the acute toxicity effect of different concentrations fluoride exposure in water environment on Cipangopaludina cahayensis were determined by static biological toxicity test. The Cipangopaludina cahayensis showed fluorosis symptoms with different degrees when they were exposed to fluoride solution. With the increase of the fluoride concentration and the passage of exposure time, the death rate of Cipangopaludina cahayensis was increased, which exhibited an obvious dose-response relationship and time-response relationship. The median lethal concentration （LC50） of fluoride of 24, 48, 72 and 96 h on Cipangopaludina cahayensis were 694.12, 642.11,542.11 and 480.77 mg/L, respectively. The safe concentration of fluoride on Cipangopaludina cahayensis was calculated as 48.08 mg/L by the established regression equation. According to the acute toxicity grading standard, the fluoride was low toxic to Cipangopaludina cahayensis.