Abstract: Elastic modulus is an important input parameter in all kinds of structural analyses. The mathematical model used to identify the structural elastic modulus with measured displacements at several points is thusly built up, and then Gradient-Regularization method, an inverse problem solution method, is employed to solve the problem. By making linear transformation, the elements along the diagonal line of Jacobi matrix can all be turned into 1 in order to enhance the computing velocity and precision. The common finite element program is compiled, and numerical examples have proved that the method is efficient. The issues such as the choice of initial value, model error and the choice of measuring points are discussed as well.