Abstract In compact hot strip mills, improving the accuracy of product strip width is an important factor in reducing production costs. This paper describes a newly developed width control system for the SSM hot strip mill. The features of the system are as follows: (a)Edger roll gap setup function based on accurate width change prediction, (b)Flexible learning function with classified learning result table, and (c)Dynamic control of the interstand tension between roughing stands and dynamic control for improved width accuracy in the region of variable width change at the head and tail ends of the material. Implementation of this new system has achieved a significant improvement in width accuracy.