The present invention relates to an alloyed hot-galvanized steel for making explosion-proofing band of colour kinescope tube, and the base sheet composition and its production method is disclosed. According to the production process of conventional alloyed galvanized steel the off-line planishing process is adopted to strictly controls the planished percentage elongation, and planishing rool is processed by grinding, polishing and frosting treatment so as to obtain the invented product. Said invention is low in production cost, simple in technological process, and its product possesses smoothand beautiful surface and excellent heat-resistant, anti-corrosion and welding properties.