Abstract: The rapid development of global industrialization and advances in science and technology have exacerbated energy shortages and amplified the impact of greenhouse gas emissions on the environment and climate. Against the backdrop of energy shortages and the urgent goal of carbon neutrality, solar-driven green hydrogen production technology has emerged as a key solution for meeting energy demands and protecting the environment. As a renewable and clean energy source, hydrogen produced through the photocatalytic decomposition of water using solar energy generates only water as a byproduct. This process achieves zero carbon emissions while offering advantages such as high energy density and environmental friendliness. ZnIn₂S₄, as a typical ternary layered metal sulfide photocatalyst, has become a research hotspot in the field of photocatalytic hydrogen production due to its inherent advantages—including a narrow bandgap, full responsiveness to visible light, and a bandgap position suitable for the hydrogen evolution reaction. However, pure ZnIn₂S₄ suffers from issues such as high photogenerated carrier recombination rates, a limited number of active sites on the surface, severe photocorrosion, and slow surface reaction kinetics, making its photocatalytic hydrogen production performance insufficient to meet practical application requirements. This paper systematically describes the crystal structure, electronic structure, and fundamental physicochemical properties of ZnIn₂S₄, elucidating its core reaction mechanisms and performance bottlenecks in photocatalytic hydrogen production; Simultaneously, this paper comprehensively summarizes the current mainstream modification strategies for ZnIn₂S₄ photocatalytic hydrogen production, including heterostructure construction, defect regulation, element doping, and co-catalyst loading, and provides an in-depth analysis of the structural characteristics, mechanisms of action, advantages and disadvantages, and typical application cases for each strategy. Finally, based on existing issues in current research, this paper outlines future development directions for ZnIn₂S₄ photocatalysts.