Photocatalytic H2 evolution by water-splitting is a prospective technology of clean energy producing, which can deal with the problems of energy and environment. A novel efficient ZnWO4/CdS photocatalyst was fabricated with the significantly effective performance of photocatalytic H2 evolution. The ZnWO4/CdS composites exhibit the promoting photocatalytic evolution activity of 792.7 μmol/h and the outstanding stability in the following reactions of 12 h. The excellent photocatalytic performance of ZnWO4/CdS composites is mainly ascribed to the efficient separation of carriers and migration of electrons from CdS to ZnWO4 via their intimate contact interfaces. Moreover, the photocatalytic mechanism, which the analysis on XPS spectrum and radical-trapping experiments provide clues for is demonstrated to explicate the enhanced performance of the ZnWO4/CdS photocatalyst. This work provides a new design of ZnWO4/CdS photocatalysts for more efficient utilization of solar energy and some new perspectives for explicating the migration process of carriers.