For the orthogonal TA2M sheet metal, a usable triangle function used to describe the variation of anisotropy R is presented. Based on above description of value R, a new hypothesis that the potential values on flange outer boundary is regularly arranged according to the distribution law of anisotropy R has been proposed and the potential theory and boundary element method are used to calculate the reasonable blank shape which will provide a good method to control the deep-drawing ear for the orthotropic TA2M sheet metal. Through practical application, the presented blank design approach is approved to be efficient for the control of deep-drawing ear.