A new type of poly(methyl methacrylate) nanocomposite containing TiO2/ Ag ( TiO2–Ag/PMMA) at low dosage of nanoparticles was prepared by microemulsion method for the first time. To investigate effect of Ag nanoparticles on the photodegradation efficiency, the nanocomposites with various TiO2: Ag molar ratios were prepared by direct in situ synthesis of Ag nanoparticles in W/O microemulsion. The fabricated nanocomposites were characterized by DRS, TEM, and XPS techniques. The TEM characterization results indicated that the TiO2/ Ag nanoparticles were well dispersed in the polymer framework with an average size of 15 nm. The formation of Ag0 decorated on the surface of TiO2 nanoparticles, acted as both a plasmonic sensitizer and an electron trap, verified with XPS analysis. The visible-light photocatalytic performance of the prepared nanocomposites was studied in degradation of acid blue 92 (AB92) dye, representative pollutant model, and compared with PMMA, TiO2/ PMMA, and Ag/PMMA as control samples. Effect of TiO2: Ag molar ratios, pH, and reusability on the photodegradation efficiency of pollutant model has been studied.