The model reduction technique was applied to solve the dynamic response. In order to make the system show the actual responses of the expected signals, the iteration procedure was then used to modify the load signals based on Tikhonov regularization load identification. Furthermore, the accuracy of the load signals was identified. The comparison of the proposed method with the traditional Tikhonov method shows that the proposed method can retain a good anti-noise characteristic, and improve the precision of load identification. The accuracy of the load identification by the proposed method is much higher than that of the traditional method.