The work aims to study the modification effects of different tannins on casein-based membranes and evaluate the effects of hydrolysable (Tara tannin) and condensed (Chinese bayberry) tannins of different contents (5%, 10% and 15%) on the properties of casein-based membranes. The casein-based membranes modified by tannins were prepared by the solution casting method. The moisture content, water solubility, water vapor permeability (WVP), opacity, ultraviolet (UV) shielding capacity, tensile property, thermal stability, morphology, antioxidant capacity and chemical structure of the modified membranes were characterized. A positive correlation between tannin content and moisture content as well as water solubility was found in membranes introduced with tara tannins, however, the opposite result was observed in those membranes incorporated with Chinese bayberry tannins. The opacity of casein-based membranes modified with tannins increased. The introduction of two tannins in casein-based membranes provided lower WVP and UV transmittance, decreased the weight loss rate and increased antioxidant capacity of resulting membranes compared with native casein-based membrane. Chinese bayberry tannins effectively contributed to good tensile strength, thermal stability and antioxidant properties of casein-based membranes. Especially when the content of tannin increased to 15 wt.%, modified casein-based membranes had the best properties. Both the two plant tannins can provide casein-based membranes better UV shielding capacity, WVP and antioxidant capacity. Chinese bayberry tannin presented better cross-linking modification capacity in casein-based membranes compared with Tara tannin, yielding a better tensile strength and thermal stability of the resulting membranes. Tannin-modified casein-based membranes have application potential in active food packaging.