Photocatalytic technology is the main function of modified carbon nitride-based catalytic materials that received attention due to their potential in the field of photocatalysis. This study aims to investigate the strengthening preparation process of modified carbon nitride materials through in-situ microscopic observation technology and evaluate their photocatalytic performance. Carbon nitride materials have become a research hotspot due to their unique optical properties and chemical stability, but there are still limitations in their photocatalytic efficiency and stability. Therefore, this study adopts metal modification methods to improve its photocatalytic activity and stability. This article first synthesizes unmodified carbon nitride materials through pyrolysis, and then introduces modifiers for surface and structure modification treatment. A detailed analysis of the microstructure of the material before and after modification was conducted using in-situ observation techniques such as high-resolution transmission electron microscopy (HRTEM). The photocatalytic performance of the material was evaluated through photocatalytic hydrogen production experiments, and the modification effect was further verified through specific surface area analysis and deactivation rate testing. The conclusion shows that compared to the original material, the modified carbon nitride material has the highest hydrogen production rate of 18.9% μ Mol/h, with a maximum specific surface area of 1281 m2/g. The lowest inactivation rate after modification is 1.2%. These results not only provide scientific basis for the modification of catalytic materials, but also point out the direction for future application development.