Resumen: Nowadays, energy shortages, carbon resource shortages, and global warming are the major challengs. The usage of photocatalysis to realize the conversion of CO2 into added-value fuels can alleviate the above problems. As a visible light photocatalyst without metal components, g-C3N4 has unique electronic structure, high catalytic activity, good chemical and thermal stability, which has caused wide attention. This article mainly summarized the basic properties and structure of g-C3N4. Besides, we introduced the commonly used preparation methods and modification methods of g-C3N4, and prospects the application of g-C3N4.