Broad absorption spectra with efficient generation and separation of available charge carriers are indispensable requirements for promising semiconductor-based photocatalysts to achieve the ultimate goal of solar-to-fuel conversion.Here,Cu3-xSnS4 (x =0-0.8)with copper vacancies have been prepared and fabricated via solvothermal process.The obtained copper vacancy materials have extended light absorption from ultraviolet to near-infrared-Ⅱ region for its significant plasmonic effects.Time-resolved photoluminescence shows that the vacancies can simultaneously optimize charge carrier dynamics to boost the generation of long-lived active electrons for photocatalytic reduction.Density functional theory calculations and electrochemical characterizations further revealed that copper vacancies in Cu3-xSnS4 tend to enhance hydrogen\'s adsorption energy with an obvious decrease in its H2 evolution reaction (HER) overpotential.Furthermore,without any Ioadings,the H2 production rate was measured to be 9.5 mmol·h-1·g-1.The apparent quantum yield was measured to be 27％ for wavelength λ ＞ 380 nm.The solar energy conversion efficiency was measured to be 6.5％ under visible-near infrared (vis-NIR) (λ ＞ 420 nm).