We designed and successfully fabricated a ZnS/CdS 3D mesoporous heterostructure with a mediating Zn1-x Cd x S interface that serves as a charge carrier transport channel for the first time. The H2-production rate and the stability of the heterostructure involving two sulfides were dramatically and simultaneously improved by the careful modification of the interface state via a simple post-annealing method. The sample prepared with the optimal parameters exhibited an excellent H2-production rate of 106.5 mmol h-1 g-1 under visible light, which was 152 and 966 times higher than CdS prepared using ethylenediamine and deionized water as the solvent, respectively. This excellent H2-production rate corresponded to the highest value among the CdS-based photocatalysts. Moreover, this heterostructure showed excellent photocatalytic stability over 60 h.