PURPOSE: To improve plating adhesive properties by zinc hot dipping the Si-containing killed steel plate of superior corrosion resistance then alloying the plating zinc to the steel plate at the specific temperature by the Si content.

CONSTITUTION: The killed steel plate containing Si>0.20% is subjected to Zn hot dipping. If the Si content of the base steel material exceeds 0.2%, the Zn plating film is largely apt to crack or peel and therefore the plating Zn is heated to be alloyed to the base steel plate. The steel plate is heated with its heating index under the conditions of formula (I) and at different temperatures if the Si content is above and below 1% so that the plating Zn is alloyed to the steel plate being the base material, whereby the cracking and peeling of Zn are prevented.