Abstract: A method for metallizing plastic by pre-plating for electroplating, forming a metal bonding layer and a metal transition layer using electro arc ion plating or magnetron sputtering in series, and then forming a metal conductive layer on the metal transition layer using the electro arc ion plating. At least forming the metal conductive layer comprises: disposing a magnetic filter device between a metal target and a vacuum chamber in which the plastic workpiece is placed, so that positively charged metal ions generated by the metal target are deflected by the magnetic filter device and then enter the vacuum chamber to be deposited on the surface of the plastic workpiece.