PVC/Ag₃PO₄ composites are prepared by solution-dipping method, and the as-prepared composites are heat-treated to release HCl from PVC molecules to obtain conjugated derivative of PVC/Ag₃PO₄(CDPVC/Ag₃PO₄) composites. The CDPVC/Ag₃PO₄ composites are characterized by XRD, SEM, UV-vis DRS, PL and XPS. The effects of preparation conditions on the visible-light photocatalytic performances of CDPVC/Ag₃PO₄ composites are investigated by evaluating the decomposition of methyl orange under visible light irradiation. The results reveal that the modification of CDPVC is beneficial to the dispersion of Ag₃PO₄ particles, and it can obviously improve the absorbance of the CDPVC/Ag₃PO₄ composites in the range of visible light and the charge separation efficiency. The CDPVC/Ag₃PO₄ composites exhibit excellent visible-light photocatalytic acitivity and stability when the mass percentage of PVC to Ag₃PO₄, heat-treatment temperature and time are 0.03%, 130 ℃, and 2 h, respectively.