A series of visible light-responsive poly(methyl methacrylate) (PMMA)/TiO2/IL nanocomposite transparent films, with different loading of TiO2 nanoparticles, were facilely prepared using an ionic liquid-in-oil microemulsion system. The microemulsion system was containing methyl methacrylate monomer as continues phase, 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) as dispersant phase, Triton X-100 as surfactant and 1-butanol as co-surfactant. TiO2 nanoparticles were dispersed into the microemulsion system, and then the oil phase was polymerized by a benzoyl peroxide initiator. Techniques such as UV-vis diffuse reflectance spectra (DRS), TEM, FTIR, XRD, FE-SEM and TGA were used to characterize the resulting nanocomposite. Methylene blue (MB) dye was used as a model pollutant to study the photocatalytic activity of this novel type of PMMA/TiO2/IL nanocomposite. As an interesting result, it is found that the prepared nanocomposite exhibit excellent photocatalytic activity under visible light irradiation and considerably higher photocurrents than bare TiO2. Moreover, influence of various operational parameters such as pH, the amount of loaded TiO2 nanoparticles and recycling of the photocatalyst on the degradation reaction was investigated in detail.