CuS nanoparticles were decorated on Fe3O4@ZnS particles for the synthesis of magnetically separable photocatalysts with magnetic Fe3O4 core, together with heterojunction interfaces between ZnS and CuS. The electron-hole spatial separation ability and photocatalytic activity can be improved by optimizing the amount of CuS grown on ZnS. The highest photocatalytic H-2 generation activity of the Fe3O4@ZnS-CuS photocatalyst reached 18000 mu mol/g(-1) h(-1). The crystalline property, morphology, optical property, photocurrent response, magnetic performance, photocatalytic performance, and separation property of the composite photocatalysts were investigated. The photocatalysts can be separated and recycled by a magnet. A mechanism of photocatalytic H-2 generation by the Fe3O4@ZnS-CuS photocatalysts was proposed. The recombination of photoexcited electron and hole was suppressed by such kind of electron transfer, leading to the enhanced activity of the Fe3O4@ZnS-CuS photocatalysts. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.