The invention discloses a cover plate with assembling and positioning functions and an electronic device with the assembling and positioning functions. The cover plate is used for being arranged on an extrusion machine shell with open pores, and the cover plate comprises a cover plate body, and a positioning mechanism. The cover plate body covers the open pores and is provided with a first side edge, a second side edge, a third side edge and a fourth side edge. The positioning mechanism comprises at least one positioning set arranged on the cover plate body, and the positioning set comprises a first rib plate, a first abutting part, a second rib plate and a second abutting part. The first rib plate is arranged on the first side edge of the cover plate body. The first abutting part is arranged on the first rib plate and is connected to the first inner surface of the extrusion machine shell in an abutting-against mode. The second rib plate is arranged on the second side edge of the cover plate body, and the position, on the second side edge, of the second rib plate and the position, on the first side edge, of the first rib plate are actually symmetrical. The second abutting part is arranged on the second rib plate and is connected to the second inner surface of the extrusion machine shell in an abutting-against mode, so that the cover plate is aligned to the periphery of the extrusion machine shell by means of deformation of the positioning set. The cover plate with assembling and positioning functions and the electronic device with the assembling and positioning functions have the advantages of being simple in structure, easy to assemble and automatic in alignment.