CdMoO4/CdS@MoS2 ternary composite was synthesized by a one-step hydrothermal process and applied into photocatalytic H2 evolution with lactic acid as a sacrificial reagent. The composite exhibited much more improved photocatalytic H2 evolution activity than those of CdMoO4/CdS, MoS2/CdMoO4, and MoS2/CdS binary composites, which may be attributed to the more efficient transfer and separation of photogenerated electron-hole pairs. The CdMoO4/CdS@MoS2 composite shows the maximum photocatalytic H2