Constructing heterojunctions through surfaceloaded catalysts is an important way to improve the photocatalytic ability. This article employs a simple and effective method of in situ anchoring spherical MnCo 2 O 4 bimetallic oxide onto sheet-like graphdiyne (GDY). GDY possesses a large specific surface area, providing ample space for anchoring MnCo 2 O 4 . By in situ sintering, MnCO 2 O 4 can be closely loaded on the GDY surface, which reduces the distance between the physical barrier and the electron transfer and is more conducive to the hydrogen evolution reaction. After anchoring MnCO 2 O 4 on GDY, the composite catalyst exhibits more excellent light absorption ability, electron transfer ability, and low efficiency of electron−hole recombination. The process of catalytic hydrogen evolution exhibits superior catalytic performance and remarkable stability. The formation of an S-scheme heterojunction offers a novel pathway for electron transportation, preserves the catalytic system's maximum redox capacity, and facilitates the involvement of a greater number of electrons in the hydrogen evolution reaction.