Hexagonal CdS and layered double hydroxides are the hot materials for photocatalytic hydrogen evolution reaction due to their unique structure and excellent performance. Here, CdS/NiCo LDH catalyst with S-scheme heterogeneous is successfully prepared by the method of electrostatic self-assembly. Compared with CdS, the hydrogen evolution performance over the appropriate CdS/NiCo LDH is increased by 3.6 times. This is because the tight coupling of the contact interface between CdS and NiCo LDH and the matching of the band gap structure improve the transmission efficiency of photogenerated electrons. Ultraviolet–visible and photoluminescence experiments have proved that the separation efficiency of electrons and holes, the light absorption intensity and the charge lifetime of the composite catalyst have been greatly improved. Additional series of characterization prove the possible S-scheme heterojunction mechanism of CdS/NiCo LDH photocatalytic hydrogen evolution.