Construction of synergistic photocatalysis system is regarded as an important concept for effectively utilizing solar energy. Herein, Ag nanoparticles decorated SnO₂ flower-like structure is designed and fabricated to synergistically realize efficient hydrogen production from water splitting. According to the results of density functional theory simulations and corresponding experimental analyses, it is identified that interfacial charge coupling of composite system intrinsically facilitate the efficient interfacial charge migration and separation. Moreover, introducing Ag nanoparticles not only expands response range of incident light for SnO₂ through LSPR effect but also reduces the hydrogen adsorption free energy in the catalytic process. Eventually, contributed by the enhanced interaction between reactants and catalysts and optimized carrier behavior, Ag/SnO₂ exhibits a faster hydrogen production rate than SnO₂. The research method designed in this paper may provide a new idea for research of photocatalyst for photocatalytic hydrogen evolution.