The invention discloses a flexible conductive polyaniline nanofiber concave-convex electrode material and a preparation method thereof, and belongs to the field of a conductive nano-material. The electrode material is formed by compounding polyaniline nanofibers and a flexible nanofiber membrane. The surface of the flexible nanofiber membrane is of a concave-convex structure, and the concave-convex structure comprises a plurality of small-volume cone-shaped bodies, cylindrical bodies or spherical bodies. The preparation method is characterized by, to begin with, soaking a flexible concave-convex base body of the electrode material into an acid aqueous solution comprising aniline monomers; then, adding a neutral aqueous solution comprising an oxidizing agent to a mixed system drop by drop; after reacting for a while, soaking the product in the acid solution; and finally, carrying out vacuum drying to obtain the flexible conductive polyaniline nanofiber concave-convex electrode material. The preparation method is simple in process, low in cost and suitable for industrialized mass production; and meanwhile, the electrode material can be widely applied to the field of supercapacitors, lithium ion batteries and sensors and the like.