Multi-component photocatalysts can take advantage of each component and overcome their shortcomings at the same time by synergetic effect, providing a great promising future for high activity photocatalyst. In this work, P3HT/Ag/TiO2 ternary photocatalyst was constructed to further promote the separation of photogenerated carriers and enhance the photocatalytic activity as much as possible by introduction of Ag nanoparticles into the conjugated polymers/TiO2 heterojunction. The results showed that different amount of Ag nanoparticles were successfully photodeposited on the surface of TiO2 to form Ag/TiO2 composites, which were subsequently hybridized with P3HT, obtaining P3HT/Ag/TiO2 ternary photocatalytic system. The ternary photocatalyst exhibit remarkably enhanced photocatalytic activity for degradation of MO compared to the single-and two-component systems under both visible light and ultraviolet illumination by varying Ag content. This should be ascribed to the favored separation of photogenerated carriers resulted from the synergistic effect of P3HT, Ag and TiO2, as confirmed by the results of photocurrent tests. However, the influence of Ag content on photocatalytic activity under various light conditions was totally different. P3HT/Ag/TiO2-1, with a very small amount of Ag, showed the highest visible light photocatalytic activity, which was 2.1 and 9.7 times that of P3HT/TiO2 and TiO2 respectively and then the photocatalytic activity decreased with Ag loading amount. For the photocatalytic experiments performed under ultraviolet light, the activity continuously increased with the Ag content within our conditions, reaching the maximum for P3HT/Ag/TiO2-4, which was 4.5 and 1.8 times that of P3HT/TiO2 and Ag/TiO2-4 respectively. This might be resulted from the different role of Ag nanoparticles, probably electron sink under visible irradiation and Z-scheme bridge between P3HT and TiO2 under ultraviolet light.