Abstract It is facing a tremendous challenge to develop the desirable hybrids for photocatalytic H 2 generation by integrating the advantages of a single semiconductor. Herein, an all‐sulfide ZnIn 2 S 4 /CdS/PdS heterojunction is constructed for the first time, where CdS and PdS nanoparticles anchor in the spaces of ZnIn 2 S 4 micro‐flowers due to the confinement effects. The morphology engineering can guarantee rapid charge transfer owing to the short carrier migration distances and the luxuriant reactive sites provided by ZnIn 2 S 4 . The S‐scheme mechanism between ZnIn 2 S 4 and CdS assisted by PdS cocatalyst is testified by in situ irradiated X‐ray photoelectron spectroscopy and electron paramagnetic resonance (EPR), where the electrons and holes move in reverse driven by work function difference and built‐in electric field at the interfaces. The optimal ZnIn 2 S 4 /CdS/PdS performs a glaring photocatalytic activity of 191.9 µmol h −1 (10 mg of catalyst), and the largest AQE (apparent quantum efficiency) can reach a high value of 26.26%. This work may afford progressive tactics to design multifunctional photocatalysts.