▎ 摘　　要

NOVELTY - Preparing graphene thin film, comprises selecting a small piece of graphene film from previously synthesized graphene thin film, transferring the small pieces of graphene thin film on substrate, inducing growth of the graphene thin film pieces at starting point using the substrate, where the substrate is solid carbon source, a liquid source, a gas source or more than two carbon source. USE - The method is useful for preparing graphene thin film (claimed), which is useful in preparation of optoelectronic device. ADVANTAGE - The method prepares graphene thin film with excellent photoelectricity in a simple manner.