The invention discloses a graphene thin film coating device and method based on PECVD. The device comprises a plurality of vacuum chambers which are linearly arranged and a flexible base material conveying mechanism which penetrates the multiple vacuum chambers; the multiple vacuum chambers comprise the unwinding chamber, the multiple coating chambers and the winding chamber which are all sequentially connected; each coating chamber is internally provided with a radio frequency toward-target device; the radio frequency toward-target devices in the multiple coating chambers form a plasma enhanced chemical vapor deposition system; an air partitioning chamber is arranged between any two adjacent coating chambers; and the unwinding chamber, the winding chamber, the coating chambers and the air portioning chambers are externally connected with a high-vacuum exhausting system. According to the method, vacuumizing is performed on the vacuum chambers till the vacuum degree reaches a set value; then a flexible base material is released by the unwinding chamber and conveyed into the coating chambers, and a graphene film is deposited on the surface of the flexible base material through a PECVD method; and finally, the graphene film is conveyed into the winding chamber to be wound. The graphene thin film coating device and method based on PECVD are uniform in coating, and the film layer manufactured on the surface of the flexible base material is high in purity.