The invention relates to an automatic cable specification sorting device which comprises a horizontally arranged barrel, a rotary table arranged in a coaxial way together with the barrel, a rotating motor and a cable screening block, wherein the rotary table is arranged at the end part of the barrel and is tangent with the inner side of the barrel; the rotating motor is fixedly arranged in the barrel; a rotating shaft of the rotating motor is connected with the center of the rotary table; the outer end surface of the rotary table is provided with a sliding groove which extends to the cylindrical surface of the rotary table along the radial direction of the rotary table; the sliding groove is internally provided with a sliding block which is connected with the end surface of the sliding groove by a first spring; the end surface at the outer side of the barrel is provided with a limiting groove which extends to the inner side of the barrel along the radial direction of the barrel; two grooves are respectively formed in the left side and right side of the limiting groove; a cable trough is formed in the inner side of the barrel and along the axial direction of the barrel, and is communicated with the limiting groove.