Semiconductor magic-sized nanoclusters have got tremendous interests owing to their distinct chemical and photophysical properties, however, researches concerning their applications are still quite limited. Herein, we employ magic-sized CdSe nanoclusters as the light absorber for hydrogen photogeneration, which exhibits much better photocatalytic performance as compared to other conventional semiconductor quantum dots, such as CdS, CdSe, CdS/CdSe, and CdSe/CdS under identical conditions. Photoluminescence lifetime and transient absorption studies indicated that the superior activity is mainly ascribed to the longer exciton lifetime and fast electron transfer from nanoclusters to cocatalyst. Moreover, the issue of instability during reaction could be significantly inhibited by anchoring Zn²⁺ onto the surface of nanoclusters, which gives the average efficacy of hydrogen evolution at 0.61 ± 0.07 mL·h⁻¹·mg_catalyst⁻¹, i.e., 27.3 ± 2.9 mmol·h⁻¹·g_catalyst⁻¹ (420 nm) with maintained 95.2% of original activity over 12 h illumination.