A method for electrochemical extraction of uranium from seawater using an oxygen vacancy (OV)-containing metal oxide includes the following steps: adding glycerin to a solution of indium nitrate in isopropanol, transferring a resulting mixture to a reactor, and conducting reaction to obtain a spherical indium hydroxide solid; dissolving the solid in deionized water, transferring a resulting solution to the reactor, and conducting reaction to obtain a flaky indium hydroxide solid; calcining the solid to obtain calcined OV-containing In2O3-x; adding the In2O3-x to ethanol, and adding a membrane solution; coating a resulting solution uniformly on carbon paper, and naturally drying the carbon paper; clamping dried carbon paper with a gold electrode for being used as a working electrode for a three-electrode system; and adding simulated seawater to an electrolytic cell, placing the three-electrode system in the simulated seawater, and stirring the simulated seawater for electrolysis to extract uranium from the seawater.