The invention discloses a graphene nanowire film and a preparation method thereof and a thin film transistor array. The preparation method of the graphene nanowire film includes steps: taking an aluminum base material as a base material to prepare a porous anodized aluminum template according to an anodizing method; depositing on pore inner wall surfaces of the porous anodized aluminum template according to an atomic layer deposition method to obtain a metal catalysis layer; depositing on the surface of the metal catalysis layer according to a chemical vapor deposition method to obtain graphene nanowires, removing the porous anodized aluminum template by a template removing agent, and removing the metal catalysis layer by a catalysis layer removing agent to obtain graphene nanowires; rinsing the graphene nanowires, dispersing the rinsed graphene nanowires into film forming solution to obtain film solution, coating the surface of a substrate with the film solution, and drying to obtainthe graphene nanowire film. By adoption of the technical scheme, great electrical conductivity of the graphene nanowire film is achieved.