Determined the best preparation method of grape seed extract by comparing the antioxidant activity of grape seed extract prepared by different preparation methods. The grape seed extract was used to preserve the freshness of post-harvest citrus, and the effect of grape seed extract on the post-harvest storage quality of citrus was studied. Stored at room temperature for 40 days, test the weight loss rate, titratable acid content, sensory quality, Vc content, decay rate and other indicators of citrus to evaluate the fresh-keeping effect of grape seed extract on citrus. The results showed that the antioxidant activity of the grape seed extract prepared by the ultrasonic-assisted reflux method is higher than that of the ultrasonic method and the reflux method; under the same storage conditions, the citrus fruits treated with the grape seed extract have better indicators than untreated fruits. The grape seed extract obtained by the research has a good preservation effect and is expected to be developed as a relatively safe, environmentally friendly and pollution-free fruit preservation agent.