Peanut protein isolate films were prepared in the presence of transglutaminase in order to improve the properties. The influences of transglutaminase on film properties,microstructure,differential scanning calorimetry and infrared spectrum of films were investigated. The results showed that compared with the control,the tensile strength, elongation at break and resistance of oxygen of the transglutaminase treated film increased by 91. 69%,53. 69% and 4. 97%,and water vapor permeability and solubility were decreased by 15. 12% and 32. 85%,respectively. After the treatment with transglutaminase,the inner holes of films were smaller,the structure became compact,but meanwhile,the thermostability of the films was decreased. The study also indicated that TGase catalyzed hydroxyl and amidogen in PPI to form amide groups,and also changed the original secondary structure of peanut protein molecules.