The composite photocatalyst Ag3PO4@P3HT with core-shell structure was synthesized through a simple method, and SEM, TEM and FTIR were used to detect the presence of P3HT in the composite catalyst and to confirm its structure. The sample's photodegradation ability was studied by degradation the organic pollutants phenol and BPA under visible light irradiation. Through experimental tests the photocatalytic activity was the highest at 0.07 wt% P3HT, and the degradation of phenol increased by about 23% compared to Ag3PO4. At the same time, and with the same concentration of BPA, the degradation increased by about 25% in 6 min. Photoelectricity, UV-vis spectroscopy, and PL testing were used to study the electrochemical and optical properties of the catalysts. It is concluded that the increase in photocatalytic activity is due to the enhancement of visible light absorption, the more efficient separation of photogenerated e(-)/h(+), and the faster transfer of photogenerated carriers. Finally, the mechanism of enhanced photocatalytic activity was discussed in terms of band position.