Abstract: In order to suppress the influence of microvibration on the imaging of the spliced telescope, modal tests and dynamic finite element corrections were performed for the mirror assembly of the co-phase device. Due to its complex structure and contact, the model is simplified, and then based on the results of the modal test, the improved cross mode-cross mode method (ICMCM) is used to correct the dynamics of the finite element model. The step response of the corrected model was solved and compared with the measured results to verify the validity of the model correction. After the correction, the first-order frequency error of the model decreases from 5.2% to 0.2%; the step response is basically the same as the displacement peaks of the six measurement points of the simulation, and the peak time, and the maximum error of the displacement peak is 8.8%. The results show that in order to simplify the mirror component and then correct it by the ICMCM method, the computational efficiency is improved while the accuracy of the model is maintained.