The poor separation and significant recombination of electron-hole pairs and slow transfer mobility of charge carriers limit the performance of BiVO4 for photoelectrochemical (PEC) water splitting. To ameliorate the above problems, a novel integrated Ag-embedded MoS2/BiVO4 p-n heterojunction ternary composite electrode is fabricated and applied. Surface plasmon resonance (SPR) of Ag nanoparticles (NPs) by the near-field electromagnetic enhancement or abundant hot electrons injection and p-n heterojunction of MoS2/BiVO4 by the built-in electrical potential synergistically boost the electron-hole pair separation, transfer properties and suppress the recombination of the electron-hole pairs. Consequently, the BiVO4-Ag-MoS2 electrode among four of the BiVO4-based electrodes achieves the largest photocurrent density of 2.72 mA cm-2 at 0.6 V vs. RHE, which is 2.44 times higher than that of pure BiVO4 electrode (0.79 mA cm-2), and possesses the largest IPCE of 51% at 420 nm. This work proposes a worthy design strategy for a plasmon enhanced p-n heterojunction for efficient PEC water splitting.