Abstract: On the basis of a large amount of data measured. the problem of rolling by plate width increase in sequence (RPWIS) for 2800 four-high mill, is analyzed. By means of the program of two-dimensional finite element method with varying thickness, the simulative model in the roll deformation or crown forecast for 2800 four-high mill is specially established. In terms of the results of simulative calculation, the influence of work roll wear contour (which appearing in a later period of work roll rolling, like basin's shape), plate width or roll force to plate crown is revealed and the effective method is pot forward to prevent RPWIS.