The freshness keeping effect of cardboard boxes with inner freshness keeping coating on the strawberries was studied. The strawberries came from Hangzhou Yuhang was used as the test object to investigate the effect of coating agents on the physical properties of strawberries, and response surface analysis was used to optimize the coating formula. Results show that the weight loss and cell membrane permeability of strawberries packaged in the cardboard boxes coated with hydrated silicon dioxide, KMnO₄ and polylysine are less than that of strawberries packaged in conventional cardboard boxes, while the hardness of strawberries in coated cardboard boxes is higher than that of strawberries in conventional cardboard boxes, that is, cardboard boxes with inner freshness keeping coating have better effect. The best freshness keeping coating formula is: hydrated silicon dioxide: 71.97%; KMnO₄: 0.136%; polylysine: 0.237%.