We present an extended model for identifying structural boundary condition parameters, considering the coupling terms (stiffness and damping) between translation and rotation which are commonly ignored in general cases. Two objective functions are established based on impulse response functions (IRFs). Frequency parameterization, which considers the minimum distance to be minimized, is employed. The inverse problem of boundary identification is then solved using Newton-Raphson method. The results of numerical simulation and experimental study assessed the performance of the proposed method.