The core-shell shaped Pt@CdS nanoparticles were successful anchored onto the surface of three-dimensionally ordered macroporous (3DOM) SrTiO3 with different pore sizes through a two-step photo-deposition method, to form a series of promising Z-scheme Pt@CdS/3DOM-SrTiO3 composites for photocatalytic hydrogen evolution from water splitting. The well-ordered inverse opal and ternary heterojunction structure of Pt@CdS/3DOM-SrTiO3 composites were well illustrated through SEM and HRTEM characterizations. The Pt@CdS/3DOM-SrTiO3 composites exhibited excellent efficiency for hydrogen evolution (57.9 mmol/g h) under UV-vis light irradiation. Through a series of controlled experiments and related characterizations, the notably enhanced catalytic performance of Pt@CdS/3DOM-SrTiO3 composites can be mainly attributed to the synergistic effect of the slow photon enhancement of 3DOM-SrTiO3, which significantly promotes the light harvesting efficiency of photo-catalysts, and the enhanced separation of photogenerated carriers because of the Z-scheme charge transfer mechanism. In addition, the ternary Pt@CdS/3DOM-SrTiO3 catalysts are very stable and can be recycled five times without any decrease in photocatalytic activity.