Abstract: With the rapid progress of society, science and technology, fossil energy is rapidly consumed, and environmental pollution is becoming increasingly serious. Develpoing a sustainable and environmentally friendly fuel energy source has become a widely discussed issue. The emergence of semiconductor photocatalysts provides a new way to solve this problem. Semiconductor photocatalysts can convert solar energy into hydrogen energy by decomposing water under the condition of light, and realize a sustainable production of green and environmentally friendly high-calorie energy. Among many semiconductor photocatalysts, g-C₃N₄ has attracted much attention due to its advantages such as simple preparation method, low cost, good stability, and suitable band structure. However, its photo-generated electrons and holes are slow to transfer and easy to recombine. The narrow absorption range and low specific surface area make its photocatalytic performance not ideal. In recent years, many scholars have conducted a lot of research on these issues to improve their photocatalytic performance. The research progress of elemental doping modification and the construction of semiconductor heterojunctions for the modification research of g-C₃N₄ are discussed; the existing problems and corresponding solutions are also analyzed, then, the following development trends are forecasted.