The challenge of synergistically optimizing different mechanisms limits the further improvement of plasmon-mediated photocatalytic activities. In this work, the CdS/Au-Ag/B-TiO2 photocatalyst, combining a heterojunction structure with localized surface plasmon resonance (LSPR), is prepared by a high-temperature hydrogen reduction and hot solvent method. The novel synergistic interaction at the interface between the electric field and the plasmon electromagnetic field drives effective charge separation with improved photocatalytic efficiency. The Cd3Ti2 catalyst exhibits the highest photocatalytic activity, and the H2 generation efficiency under the full solar spectrum is 15.97 mmol⋅h−1⋅g−1 with good stability as high as 81.3% in 24 h cycles. The CH4 and CO precipitation performances are achieved at 14.2 μmol⋅h−1⋅g−1 and 113.9 μmol⋅h−1⋅g−1, respectively, in the CO2RR process. The design of the synergistic mechanism of the dual electric field offers an important development in the field of plasma-mediated photoredox catalysis.