▎ 摘　　要

NOVELTY - The method involves judging the cleanliness of a graphene film surface by the size of a contact angle of water and a graphene film. The cleanliness refers to a clean area of the graphene film surface and the proportion of the surface area of the graphene film. The graphene film of known cleanliness and the graphene film to be measured is prepared respectively. The cleanliness of the surface of the graphite or boron nitride thin film is judged by the size of the contact angle between water and the graphite or boron nitride thin film. USE - Method for evaluating cleanliness of graphene film used in electrical, optical, thermal and mechanical aspects. ADVANTAGE - The method is fast, lossless, and large area evaluating the cleanliness of the graphene film. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a to be tested graphene film surface contact the test pattern.