Harnessing renewable solar resources to drive water electrolyzer to attain hydrogen fuel is of paramount significance to a sustainable energy future. Nevertheless, the intermittent and instable drawbacks of sunlight greatly limit their practical applications. In this sense, incorporating an energy storage module in between the photovoltaic and electrolytic cells separately is an effective solution to cushion this issue. Herein, we devise a solar-driven self-powered electrocatalytic water splitting system, which employs photovoltaic cell to drive micro zinc-ion battery array to offer a stable voltage for continuously powering the seawater electrolyzer. Our design of miniature energy storage devices not only harvests high energy output but also reduces the bulky connection degrees of thus-integrated system. More impressively, the electrodes based on earth-abundant materials showcase multifunctionality, which is reflected in the good electrochemical performance of zinc-ion battery device, the impressive electrocatalytic activity toward overall water splitting, as well as the robustness to resist the corrosion within alkaline seawater. Our hybrid system would open up agitated ideas for the continuous acquisition of hydrogen fuel with low energy consumption, reasonable cost aspect and high environmental sustainability.