The invention discloses a method for preparing a large-area graphene film. The method comprises the following steps of pouring a graphene oxide aqueous solution on a paper base material to obtain a uniformly-covering graphene oxide film, carrying out drying curing treatment, and dipping the paper base material with the graphene oxide film into hydroiodic acid for a reduction reaction, wherein in the reduction reaction, the paper base material is hydrolyzed under the acidic condition and simultaneously, reacts with an acid to produce bubbles so that the graphene oxide film is automatically separated from the paper base material and the large-area graphene film product is obtained. The invention also discloses a method for preparing the graphene film or large-area graphene composite films. The methods can realize graphene reduction without a high-temperature or a toxic reduction reagent, can conveniently and fast realize film stripping to produce large-area film products and are suitable for large-scale industrial production.