A novel ternary graphene oxide (GO)/Ag3PO4/AgBr composite was synthesized by an in situ growth of Ag3PO4/AgBr on GO nanosheets. The photocatalytic efficiency of the nanocomposite under visible light irradiation was much enhanced due to the coupling of GO nanosheets and Ag3PO4/AgBr, which enlarged the absorption region, facilitated the charge transportation, and enhanced the charge collection efficiency. According to the photocatalytic results, the 0.625%GO/Ag3PO4/AgBr sample shows the highest photocatalytic activity, about 3.6 times higher than that of Ag3PO4. According to the radical trapping test, the center dot O-2(-) and center dot OH radicals, together with h(+) are the dominant active species in the GO/Ag3PO4/AgBr photocatalytic process. A possible photocatalytic mechanism for photocatalytic degradation over GO/Ag3PO4/AgBr was proposed.