In this study, we developed an novel approach by creating a flower-like p-n heterojunction, where NiCo2O4 (NCO) nanoparticles are deposited onto flower-like hierarchical ZnIn2S4 (ZIS) microsphere, to facilitate photocatalytic H2 evolution from water. Theoretical calculations and experimental results underscore the synergistic effects of the heterojunction and photothermal properties in the NCO-ZIS composite, leading to a significant enhancement in photocatalytic activity. Detailed investigation of photocatalytic mechanism elucidates how the heterojunction bolsters carrier separation and suppresses carrier recombination, while the photothermal effect broadens light absorption, elevates reaction temperature, accelerates carrier migration, and reduces activation energy. Therefore, the NCO-ZIS heterojunction exhibits exceptional hydrogen evolution performance, reaching to 4507 μmol h−1 g−1, which surpasses ZIS alone by 5.04 times. This research lays the groundwork for designing highly active photothermal catalyst with broaden-spectrum solar energy utilization.