Crown adjustment capacity of the 3-order continuously variable crown(CVC) roll is proportional to the square of strip width,which is inevitably insufficient to the need of the narrow band strip when it is employed on the wide/ultra wide strip mills.Based on a deep research of the variable crown roll's contour design theory and the lateral roll gap formation mechanism,a method that uses quadratic polynomial curves to linearize roll gap is proposed.With this method,the complete linearly variable crown contour and the mixed variable crown contour are designed,whose crown adjustment capacity is not only proportional to axial shift position of work rolls,but also proportional to strip width in the whole width range or in the desired width band respectively.Compared with CVC contour,mixed variable crown contour ensures a less difference of the roll diameter and a stronger crown adjustment capacity,suitable for both wide and narrow strip,therefore,enhancing shape adjustment capacity and the overall performance of mills.