The utility model discloses a plasma surface polarization treatment device suitable for repairing, restoring and site crack mending of a polyethylene(2PE,3PE) anticorrosive coating of a steel pipeline, relating to the technical fields of plastic molding or connecting, general corrosion prevention or rust prevention of metal materials and pipeline systems. The plasma surface polarization treatment device consists of a bridge rectifier circuit, a capacitance filter circuit, an inverter circuit, a high-frequency coupling transformer, a high-frequency high-pressure transformer and electrodes. 220V AC current sequentially runs through the rectifier circuit, the filter circuit, the inverter circuit, the high-frequency coupling transformer and the high-frequency high-pressure transformer and then is connected to a plasma treatment electrode(7)and an electrode consisting of ground wire magnetic catches(11). The polarization treatment device is even, efficient and stable in polarization treatment, good in modification effect, high in treatment efficiency and simple in structure and is convenient to operate and practical.