Efficient use of solar energy for photocatalytic organic synthesis and degradation of organic matter is one of the most promising ways to solve energy shortage and environmental pollution. Silver/sulfur‐doped polyimide (Ag/SPI) was successfully prepared by anchoring silver nanoparticles on sulfur doped polyimide with dendriform structure by an open‐loop and closed‐loop method. Through the analysis of the structure, morphology and photoelectric properties by different characteristics, it is found that the anchoring of silver nanoparticles greatly reduces the electron‐hole recombination rate of SPI, and the cyclic stability is relatively good, and the electrons generated by photoexcitation can participate in the reduction of p‐nitrophenol more. Therefore, the activity of degradation of organic pollutants was greatly improved under the irradiation of visible light. At 5 minutes, the degradation rate of p‐nitrophenol reached 100 %, and the only product p‐nitrophenol was generated. The reaction time was 12 times that of SPI without anchored metal particles. The Ag/SPI dual‐function catalyst provides a new idea for the application of p‐nitrophenol wastewater treatment and the conversion of p‐aminophenol and provides a new reference direction for the field of organic wastewater treatment and organic synthesis.