Abstract: In order to align large sparse aperture telescope, the application of screw theory for assembling by the serial robot arm was investigated. Firstly, the basic principle of the serial robot arm alignment for large sparse aperture telescope was analyzed by screw theory. Secondly, based on the screw theory and geometric relation, the principle of the sparse aperture telescope assembling was analyzed and the error analysis was carried out. After that, the feasibility of the installation of point source microscope(PSM) on serial robot arm was analyzed and tested. It was proved that PSM on robot arm was similar to the case in laboratory environment for image stability. In the end, the application of serial robot arm combined with PSM in the large sparse aperture telescope alignment was analyzed.