PURPOSE: To provide a jig for electroplating only the top land and the skirt portion of an aluminum piston for use in an internal combustion engine and a low-cost electroplating method which uses the jig.

CONSTITUTION: A piston is inserted from a piston crown into a jig 11 comprising a head cap 12 to which the crown surface of the piston abuts, a masking ring 12 covering ring grooves and a land portion located between the grooves, and a joint 14 for holding the cap and the ring 13 at an interval equal to the width of a top land, and then the piston crown is made to abut to the head cap and a vinyl chloride band or a round wire 16 is wound to the outer peripheral surface of the masking ring 13 for insulation and electroplating is performed.