Assortment optimization problems intend to seek the best way of placing a given set of rectangles within a minimum-area rectangle. Such problems are often formulated as a quadratic mixed 0-1 program. Many current methods for assortment problems are either unable to find an optimal solution or being computationally ineffecient for reaching an optimal solution. This paper proposes a new method which finds the optimum of assortment problem by solving few linear mixed 0-1 programs. Numerical examples show that the proposed method is more computationally efficient than current methods.