The high cost and low carrier separation efficiency of g-C3N4/Ag2O photocatalysts affect its application in the degradation of organic pollutants. In this study, the CA--CD/g-C3N4/Ag2O 2D/0D heterojunction photocatalysts were successfully prepared to enhance the visible light response and inhibit the electron-hole recombination simultaneously during pollutant degradation. The 10 : 1 : 1 CA-β-CD/g-C3N4/Ag2O showed the outstanding photochemical catalysis performance for the degradation of organic pollutants. The degradation efficiency of methyl orange, reactive black and norfloxacin was 2.53, 1.92 and 1.14 times than that of 1 : 1 g-C3N4/Ag2O. In addition, 10: 1 : 1 CA-β-CD/g-C3N4/Ag2O also showed excellent photocatalytic stability. The free radical scavenging experiment and electron spin resonance proved that ∙O2 - was the chief active specie in the degradation process. The mechanism research results showed that the formation of heterojunction improved the utilization rate of sunlight and promoted the separation efficiency of photo-generated electrons and holes, which significantly advanced the photocatalytic activity of the composite catalyst. The preparation of CA-β-CD/g-C3N4/Ag2O provided ideas for modification of photocatalyst by macromolecular organic matter.