An automatic and quick adjustment method for zero interference fringes was proposed to meet the requirement of high precision subaperture stitching interferometry . The influence of interference fringe numbers on stitching errors was analyzed, and the analyzed results show that the interferometer return error is less than λ/50(PV value) when the interference fringe numbers of subaperture are less than 5. A subaperture stitching measurement apparatus was optimized, and an auto-compensation method of angular displacement deviation for the motion stage was proposed. By which, zero fringe of each subaperture was realized, and the cumulative error of subaperture stitching was controlled finally. A 450mm×60mm flat mirror was measured by subaperture stitching interferometry, the experiment result shows that the surface distributions of automatic stitching measurement results are more consistent with that of the zero fringe measurement by manual adjustment , the measuring speed and measuring efficiency are improved and the measuring time is reduced by 5 min on average. As compared with zero fringe measurement by manual adjustment. The proposed method not only completes the automatic positioning and automatic adjustment of the interference stitching measurement apparatus, but also improves the measuring repeatability and detection efficiency.