Localized surface plasmon resonance applied in catalytic and optical field has attracted more attentions in recent years. Plasmonic MoO3-x nanosheets with tunable oxygen vacancies were constructed via facile solvothermal method. The as-prepared MoO3-x nanosheets were found to have LSPR absorption band centered at 680 nm, and exhibited excellent photocatalytic performance in photodegradation of organic dyes and tetracycline under visible light irradiation. X-ray photoelectron spectroscopy showed the higher content of surface oxygen vacancies in MoO3-x (88 mmol). Photocurrent, electrochemical impedance spectroscopy and photoluminescence results demonstrated that MoO3-x (88 mmol) exhibits the best photo-induced electron hole separation efficiency and the highest charge transfer efficiency. Taken together, oxygen vacancies are not only responsible for the light harvesting in the visible and near-infrared region via LSPR, but also play a key role in greatly suppressing the recombination of photoexcited carriers. Moreover, electron paramagnetic resonance revealed that photoinduced h(+) and center dot OH radicals act as the main reactive species participating in the photoxidation process.