The present invention provides a fluorine-free water- and oil-resistant coating composition comprising 30 wt % to 97 wt % biodegradable polymer in dry weight, less than 25 wt % crosslinking agent in dry weight, less than 25 wt % nanoparticles, less than 15 wt % plasticizer, less than 15 wt % surfactant and less than 1 wt % antifoaming agent in dry weight. The fluorine-free water- and oil-resistant coating composition relates to green chemistry and demonstrates both water resistance and grease resistance.