Graphene oxide (GO)-AgIO4 nanocomposites with excellent photocatalytic performance have been prepared through a facile ion-exchange method. The as-prepared samples are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy. The GO-AgIO4 nanocomposites exhibit an enhanced photocatalytic activity in the degradation of organic pollutants as compared to bare AgIO4. It is revealed that the introduction of GO can relieve the agglomeration of AgIO4 particles, enhance the light absorption of the materials, and promote the separation of photoexcited electron-hole pairs. In addition, the possible transfer and separation behaviors of the charge carriers and the photocatalytic mechanism are discussed in detail. The excellent photocatalytic performance makes the GO-AgIO4 nanocomposites a promising photocatalyst for organic pollutant treatment.