The invention discloses a nitrogen-doped carbon material modified silver phosphate composite photocatalyst, a preparation method and application thereof. The silver phosphate composite photocatalyst comprises a nitrogen-doped carbon material, and silver phosphate particles are loaded on the nitrogen-doped carbon material. The preparation method comprises the following steps: preparing the nitrogen-doped carbon material into a nitrogen-doped carbon material dispersion liquid, adding an Ag<+> solution to prepare a nitrogen-doped carbon material / Ag<+> dispersion liquid, and adding an HPO4<2-> solution to prepare the silver phosphate composite photocatalyst. The silver phosphate composite photocatalyst disclosed by the invention has the advantages of high photo-induced electron-hole pair separation efficiency, strong light corrosion resistance, strong photocatalytic activity and the like, is a novel efficient visible light photocatalyst, can be widely applied to removal of organic pollutants in the environment, and has very high use value and very good application prospect. The preparation method of the silver phosphate composite photocatalyst has the advantages of simple process, operation method, low cost, greenness, no pollution and the like, is suitable for large-scale preparation, and is beneficial to industrial application.