Ag2O/ZnO/nanographene platelets (AZNGP) composites were synthesized by the microwave assisted colloid method. The prepared samples were applied in photocatalytic reduction of methylene blue. The morphology and phase structure of the synthesized samples were characterized using field emission scanning electron microscope, x-ray diffraction, energy-dispersive x-ray spectroscopy, and transmission electron microscope. The Ag2O/ZnO/nanographene platelets composites properties were further investigated using diffuse reflectance spectroscopy, BET measurements. The catalytic activities of Ag2O/ZnO/nanographene platelets with different concentrations of nanographene platelets were studied. The results showed that photocatalytic efficiency improved with increasing nanographene platelets up to certain level and then decreased as the concentration of nanographene platelets is further increased. To understand the role of primary active control experiments by adding scavengers for electron, hole, hydroxyl oxide were carried out. The detailed mechanism will be discussed and correlated with the properties of Ag2O/ZnO/nanograpehene platelets composites.