The work aims to treat PLA films with low temperature plasma to improve their hydrophilicity and adhesion, in order to provide a method for the preparation of PLA/CNF film. Single factor experiment was used to investigate the influence of discharge voltage (50-175 V) and discharge time (10-50 s) on the surface hydrophilicity and adhesion of PLA films during low temperature plasma treatment. The surface contact angle of PLA film and the peel strength of PLA/CNF film were measured to analyze the changes of hydrophilicity and adhesion. The surface morphology was observed by atomic force microscopy; the mechanism of surface property changing from hydrophobicity to hydrophilicity was analyzed according to the X-ray photoelectron spectroscopy results, and the mechanical and barrier properties of PLA film were analyzed. PLA film had the best hydrophilicity and adhesion with CNF film after treated by low temperature plasma (125 V discharge voltage, 40 s discharge time, 4.5 cm electrode distance, 1 mL/min oxygen flow rate and 16.0 kPa vacuum degree). At this time, the contact angle of the PLA film reduced from 90° to 42.4°, and the peel strength of PLA/CNF film was 39.5 N/m. Low temperature plasma treatment changes the hydrophobic surface of PLA film to a hydrophilic one, and the treated PLA can be firmly stuck to the CNF film, thus providing a feasible method for the preparation of PLA/CNF film. Meanwhile, low temperature plasma treatment does not affect significantly the mechanical and barrier properties of PLA film.