The invention relates to an even sizing mechanism for thin films. The even sizing mechanism comprises a side vertical plate, a transmission roller, a glue roller, a glue containing disc, a glue rollermotor, a motor support, a transmission roller adjusting device and a glue scrapping device. According to the even sizing mechanism, the transmission roller is arranged on a lifting plate, the liftingplate is arranged on a supporting device on the outer side of the side vertical plate in a sliding manner, lifting of the transmission roller is achieved, the distance between the transmission rollerand the glue roller is adjustable, and the sizing requirement of the plastic thin films in various specifications is met. In addition, the glue scrapping device is arranged at the front end of the glue roller, a glue scrapping rod on the glue scrapping device is driven by the motor, and as the diameter of the glue scrapping rod is smaller, driving is convenient; and after sizing on the plastic thin films is completed, the surfaces of the plastic thin films are evenly coated, and sizing on the plastic thin films is more even and better in quality.