The invention relates to a preparation method of a graphene film strip with a linear section. The method comprises the following steps: in the dry jet wet spinning process of polyacrylonitrile precursors, arranging a hot roll calendering process before steam drafting and after drying densification, wherein the surface temperature of the calendered hot rolls is controlled at 150-200 DEG C, the interval between every two hot rolls is controlled at 0.3-0.55 mm; calendering the precursor with a round section; carrying out steam drafting and thermoforming to prepare a graphene film strip precursorwith a linear section; and preoxidating and carburizing to prepare the graphene film strip. The invention has the advantage of simple process; the prepared graphene film strip has outstanding properties, and the tensile strength exceeds 5000 MPa; and the graphene film strip has better orientation structure, the graphene layers of the graphene film strip are more compactly arranged and select preferred orientation in the axial direction, the consistency of every two adjacent graphene layers is good, and several graphene layers are compactly arranged to form a long ordered orientation structure.