This paper mainly introduces hardware design and control method of the system which is used for detecting the MA segmented mirrors in the LAMOST. According to the demand of sub-aperture stitching interferometer, the system adopts a control card to control the stepping motor to drive the worktable moving on the X-Y. The MA sub-mirror surface will be changed through active optical correction and add-subtract power of force actuators. The detection result of the MA segmented mirror of 14 shows that root mean square (RMS) of

surface accuracy error is 21.387nm less than 0.035λ (λ =632.8nm). It is demonstrated that the control system can work very well and shorten the time of detection.