The ternary nanocomposite of g-C3N4/reduced graphene oxide/ZnS (CN/RGO/ZS) has been prepared through a facile precipitation route for the first time. The as-prepared CN/RGO/ZS composite exhibit distinctly enhanced photocatalytic activities toward the degradation of Rhodamine B (about 97% after 60 min) under visible light irradiation, which was about 1.04, 1.17 and 5.38 times higher than those of CN/RGO, CN/ZS and RGO/ZS. The enhanced photocatalytic performance of RGO/CN/ZS composite arises from the synergistic effects of three components: effective charge separation, multistep transfer between CN/ZS heterojunction and RGO nanosheets, and enhanced visible-light absorption. The relative mechanism has been investigated by active species trapping and ESR analysis. This work may provide useful insights to design and construction of CN-based ternary composite photocatalysts with enhanced photocatalytic activity. (C) 2016 Elsevier B.V. All rights reserved.