Because of saving material, tapered element is widely used in practical engineering. But the calculation of tapered element is very complicated due to its different section forms. By comparing and analyzing the traits and limitations of traditional calculation methods, a new model which is suitable for any tapered element with variable sections was proposed. On the basis of energy method, the model was deduced by a given displacement function. And then through using quadratic polynomial instead of the complex moment of inertia, elastic stiffness matrix of any element with tapered beam member and equivalent nodal load under different kinds of loads were obtained. This method reduces the number of element and degree of free in structure calculation and is relatively simple in theory. The results are compared with two classical examples and ANSYS’s. It shows that the proposed method has good precision in the solution of tapered members.