Abstract: Aiming at the problems of poor flatness, excessive transverse thickness deviation and within-strip thickness variation, as well as the resulting strip breakage during the production of cold-rolled silicon steel, this paper takes a Sendzimir twenty-high rolling mill of Henan Iron and Steel Group as the research object, and systematically analyzes the influences of raw materials, processes, equipment and control measures on strip flatness accuracy. By establishing raw material inspection and preheating systems, optimizing rolling process parameters including pass reduction rate, tension and rolling speed, improving roll management and grinding accuracy, and adopting a coordinated control strategy for intermediate roll shifting and back-up roll crown, the strip flatness quality is greatly improved and the risk of strip breakage is effectively reduced. Industrial practice shows that the finished product rate, first-grade product rate and equipment operation rate of the mill are significantly increased after optimization, which verifies the engineering effectiveness and practicability of the proposed flatness control technology.