The invention relates to the technical field of overhead lines, and particularly relates to a traction system for an overhead line. The traction system comprises an installation shell, wherein wire passing notches are formed in the two ends of the installation shell, a wire inlet notch is formed in the installation shell, an elastic clamping plate is arranged in the installation shell, the elasticclamping plate is arranged in a bent mode and provided with a closed end and an open end, and the open end of the elastic clamping plate is connected with the wire inlet notch; a clamping assembly which comprises two supporting pieces arranged in the installation shell in a sliding mode, wherein the two supporting pieces are located at the two ends of the wire inlet notch in the width direction respectively, traction wheels are rotationally borne on the sides, close to each other, of the two supporting pieces, first springs are arranged at the ends, away from each other, of the two supportingpieces, and the ends, away from the supporting pieces, of the first springs are connected with the inner wall of the installation shell; and a cleaning assembly which is arranged on the supporting pieces and used for cleaning sundries on the line. When the system moves along the line, the cleaning assembly can clean the sundries on the line, use is very convenient, physical power is not consumed,and the system can adapt to the line higher than the ground.