Due to the problems of very serious wear, serious scale and poor ability to controlling strip shape of work roll, considering the advantages/disadvantages of HSS roll and the field practices, a 3D elastoplastic FEM model of rolls system with strip, which is used to analyze the ability of strip shape control of rolls system when HSS rolls work at any two stands of F1-F4, is modeled. The calculating results sho: The control ability of mill is relative greater when HSS rolls are used at F4, the advantages of HSS roll are not taken fully if HSS rolls work at F1 and F2. And HSS are available for either F2 or F3, furthermore, F3 is better for shape control. The analysis results are verified by the experiments. A strong theory base of application of HSS rolls in Hot Strip Mill is brought forward in this paper.