PURPOSE: To improve quality of plating, to prevent nonplating and to improve the plating adhesion by subjecting high Si steel whose surface has been ground by a prescribed thickness to oxidation and reduction under prescribed conditions and thereafter plating it with Zn molten metal contg. specified Al, Mn and Fe.

CONSTITUTION: The surface of a high Si steel sheet contg., by weight, 0.3 to 3% Si is ground by 0.1 to 3μm. This steel sheet is heated in an oxidizing atmosphere to form ≥0.3g/m iron oxide on the surface. Next, the steel sheet is heated and reduced in a reducing atmosphere. Then, the steel sheet is plated with Zn molten metal constituted of 0.05 to 0.3% Al and 0.1 to 5% Mn, and the balance Zn and is furthermore subjected to alloying heating treatment.