||Conjugated polymers were used for sensory materials due to large signal amplification by trace amount of analytes. Conventional conjugated polymers, however, are only soluble in organic solvents, because they are commonly a hydrophobic in nature. Water-soluble conjugated polymers have attracted much attention because of their detection applications for anion. Fluoride exists naturally in water sources and is derived from fluorine. In high concentrations, soluble fluoride is toxic and skin or eye contact with high concentrations of fluoride is dangerous. Herein, we synthesized a novel water-soluble conjugated polymer, which had good solubility in water. Fluorescence change was observed when fluoride ion was added into the polymer aqueous solution.