In this study, a ZnCo2O4/Ag3PO4 composite catalyst was prepared by the precipitation method, and its photocatalytic degradation activity for methyl orange (MO) was studied. The catalysts were characterized by TEM, XRD, EDX, HRTEM, SAED, SEM, XPS, and UV-Vis-DRS. The results indicate that 0.1 ZnCo2O4/Ag3PO4 The composite system has a good photocatalytic degradation effect on methyl orange. Under 30-minute simulated sunlight conditions, the degradation rate can reach 94%. The results show that the maximum reaction rate constant of 0.1 ZnCo2O4/Ag3PO4 is 0.05301 min-1, which is three times the size of pure Ag3PO4 and 52 times the size of pure ZnCo2O4. After three cycles, 0.1 ZnCo2O4/Ag3PO4 still degraded methyl orange (MO) at a rate of 84.4%. The trapping experiment showed that hole (h+) and O2- played the most important roles in the photocatalytic degradation field of methyl orange (MO) by 0.1 ZnCo2O4/Ag3PO4, and hydroxyl radical (OH·) played a partial role. The energy level structure of ZnCo2O4/Ag3PO4 is conducive to the effective separation of photogenerated electrons and holes, improving the lifespan of photogenerated charges. Among them, the photocatalytic performance of 0.1 ZnCo2O4/Ag3PO4 is the most excellent.