Abstract: Solar energy, a kind of clean energy inexhaustible and scattered over the world, will become an important part of new clean energy in the future. At present, in addition to solar photovoltaic power generation, there are also some other ways of using solar energy such as turning solar energy into chemical energy through artificial photosynthesis and producing hydrogen by decomposing water with semiconductors. Cu₂ZnSnS₄ is a compound semiconductor photovoltaic material that is cost-effective and environment-friendly and has excellent performance in photovoltaic power generation. It is also a suitable material for producing hydrogen through solar water splitting. Some typical achievements regarding the Cu₂ZnSnS₄ solar cell and solar water splitting devices in the past several years are introduced.