Abstract: The structural design and performance test of the sub-mirror co-phase correction device were finished. The device covered two-stage structure and was mainly composed of coarse adjustment stage, fine adjustment stage and lateral unloading mechanism. Based on the finite element method, the overall design and the performance analysis of the device were finished, and then the prototype development and basic performance test were also completed. Finally, the test results indicate that the displacement of adjustment system is about ±2.5 mm, the accuracy is about 30 nm RMS, and the natural frequency is about 70.3 Hz with analog mirror, which are in good agreement with the finite element analysis results. In conclusion, the performance of the design meets the requirements of the segmented-mirrors.