The molecularly imprinted polymers were synthesized with CH3Hg+ as a template,4-vinylpyridine as a functional monomer.8-Mercaptoquinoline was used as both a complex-forming agent and a fluorescence tag.The free-radical polymerization was performed within PVDF films and was initiated by 4,4′-azobisisobutyronitrile at 65 ℃ in dimethyl sulfoxide.The polymer showed a high selectivity for methylmercury ion.The optimum pH value was at 7.0.The detection limit for the method was up to 3.5×10-7mol/L.The polymer was applied in the determination of methylmercury ions in real water samples.The method showed a high selectivity against other metal ions and the recoveries for methylmercury ions were in the range of 93%-104%.