Chitosan (CS) based edible coatings has been widely applied in postharvest preservation in fruit and vegetables. In this work, the incorporation of chlorogenic acid onto chitosan was conducted using free radical mediated grafting procedure. The effects of chitosan grafted with chlorogenic acid (CS-g-CGA) complex on postharvest quality of peach fruit stored at 20 °C for 8 days were investigated. Structural properties of CS-g-CGA were characterized by UV–vis absorption, fourier transform infrared (FTIR), and nuclear magnetic resonance (NMR) spectra. The results showed that CS-g-CGA had a significantly higher antioxidant activity than the native CS. Furthermore, the antioxidant activity increased with the increase of grafting ratios. In vivo test, CS-g-CGA treatment better maintained firmness, soluble solids contents, titratable acidity, and l-ascorbic acid contents, and inhibited the increase of weight loss, decay index, and respiration rate of peach stored at 20 °C for 8 days. Our results suggest that CS-g-CGA holds great potential as preservative agent and edible coating material in peach fruit.