Abstract: Based on the characteristics of the cone type roll and the characteristics of the roll-shell spatial contact curve, the mathemantic expressions for the said spatial contact curve and the model for defor mation area are deduced by means of mathemantic analysis. An analysis for the features of the spatial contact curve and the deformation area is carried out,i.e.,the spatial contact curve has an interpoint at the position where x=0,and for the model of deformation area there exists a special section within the range of (X)<20~30mm. The differential error analysis and computer program calculation show that the above mentioned mathemantic model has the accuracy high as △rmsx<4×10^-5mm.