As the system with the highest solar hydrogen conversion efficiency, the further improvement of photovoltaic-photoelectrocatalysis (PV-PEC) efficiency is dependent on the light transmittance, activity and stability of the photoanode. Here, a highly permeable BiVO4 thin film was fabricated through controlled magnetron sputtering. The thickness of the thin film was merely 345 nm, while its transmittance in the visible light range reached as high as 70%. Moreover, large-scale production of such films could be achieved. By incorporating NiFeOx oxygen extraction cocatalyst, under AM 1.5G illumination, the photocurrent density at 1.23 V on reversible hydrogen electrode (RHE) increased to 4.2 mA cm−2 and the incident photon-current conversion efficiency reached 70%. A PV-PEC system was designed to efficiently harness sunlight by integrating the photoanode with a solar photovoltaic panel. Upon connection with the solar photovoltaic panel (with an efficiency of only 7%), spontaneous water decomposition could be achieved, resulting in a solar-to-hydrogen conversion efficiency (ηSTH) of 4.2% for the series system. This study contributes to the realization of cost-effective and highly efficient PV-PEC hydrogen production.