The invention discloses a silicon wafer cleaning agent and a use method thereof. The silicon wafer cleaning agent consists of oxidant, organic base, penetrant and water, and the volume ratio of the components is as follows: oxidant : organic base : penetrant : water equal to 0.02-0.1:1-4:0.5-1:30-50; the standard electrode potential of the oxidant is not less than 1.7V, and the oxidant is ozone or hydrogen peroxide; the organic base is selected from one or more of the following components: triethanolamine, sodium alkoxide, sodium alkyl, lithium alkyl, lithium amide and quaternary ammonium base; and the penetrant is fatty alcohol-polyoxyethylene ether or sodium diethylhexyl sulfosuccinate. The cleaning agent can be simply operated, silicon wafer cleaning does not become complex, the cost is low, no pollution is generated, and the cleaning agent cannot bring impurities to stain silicon wafers, and is environment-friendly.