An efficient and stable CdS@MoS₂ core@shell heterostructure was prepared by using a facile solvothermal approach. The MoS₂@CdS heterostructure reveals efficient charge separation, giving rise to excellent performance on H₂ generation from photocatalytic lactic acid decomposition. Thanks to the MoS₂ shell protection, CdS corrosion was significantly prohibited, thus resulting in the long-term photocatalytic stability of the CdS@MoS₂ heterostructure. The corresponding charge transfer properties and catalytic mechanism have been analyzed and discussed in detail. The present study provides a novel insight into the design of high performance and cost-effective photocatalysts.