To meet the quality requirements of "Dead Flat" rectangular section super flat material such as wide electrical steel sheet in the new generation of high-tech tandem cold rolling mill, an integrated simulation model of 6-high tandem cold rolling mill was established by explicit dynamic finite element method. The accuracy of the finite element model was verified by field industrial rolling test data. The influence of different rolling factors on the crown of load roll gap in complete rolling process of electrical steel is analyzed quantitatively. Based on the shape control mechanism of 6-high UCM cold rolling mill and EDW-N(Edge Drop Control Work Rolls for Non-shifting of the Work Rolls) work rolls independently designed by our research group, the bending force mathematical model of rectangular section control of electrical steel in 6-high tandem cold rolling mill was established. The parameters of the bending force mathematical model were determined by finite element simulation and field industrial rolling test data, and its accuracy was verified. The continuous test feedback data of a large 1 420 mm six-high tandem cold mill show that the high precision average C15≤7 μm ratio of electrical steel has been increased from 38.58% to 67.74%, which gives full play to the high precision shape control ability of the 6-high tandem cold rolling mill and can control the shape quality in a wide range. It provides innovative solutions and implementation paths for solving the bottleneck problem of rectangular section control of 6-high UCM cold rolling mill for non-shifting of the work rolls.