Control of increasing silicon is the emphasis and difficulty in low Silicon varieties steel smelting , the Nisco Wide Plate/Coil Plant, using oxygen residual operation in converter tapping; oxygen residual & increasing temperature ,deoxidation , desulfurization & made slag in refining furnace; protection cast, blowing argon by plugged nozzle, blowing argon by submerged entry nozzle in continuous casting, and other series methods of improving technological & operation , to control the increasing silicon content in molten steel keeping within 200×10^-6 through whole steelmaking process, the final content of the molten steel could come up to the technical standards for low silicon steel completely.