One-step synthesis of ZnO-Y2O2S:Eu(3+) (ZYE) composites were carried out using a microwave-assisted reaction of the ZnO precursor with a Y2O2S:Eu(3+) suspension using a microwave synthesis system. The photocatalytic performance in the degradation of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO) was investigated. The results show that Y2O2S:Eu(3+) phosphors play an important role in the enhancement of visible light photocatalysis and ZYE composites exhibit much higher enhancement of visible light photocatalytic performance in the degradation of MB than RhB and MO mainly due to the light down-converting effect of Y2O2S:Eu(3+), which facilitates the self-sensitized destruction of MB.