To solve the issue of incomplete single-time measurements in testing large-aperture convex aspheric surfaces by the fringe reflection method, this study proposes a three-dimensional stitching of fringe reflection method based on the rotary table and marking points. In this method, the optical path is simulated by ray tracing first, and the stitching sub-apertures are divided for convex aspheric surfaces with different parameters. Then, the sub-apertures are sequentially measured by the fringe reflection method. Meanwhile, the coordinates of the marking points on the rotary table are obtained by the stereo vision technology, and the coordinates of the marker points are used to unify the sub-apertures into the same coordinate system, so as to complete the preliminary stitching. Finally, the iterative closest point algorithm is utilized to carry out high-precision stitching, and the complete surface is ultimately reconstructed. A three-dimensional stitching measurement system is actually built to test a convex hyperbolic mirror with an aperture of 150 mm, the surface figure of the mirror has the peak to valley (PV) of 1.72 μm and the root mean square (RMS) of 0.39 μm. The stitching result is compared with the full-aperture results from the LuphoScan profilometer, which has the PV of 1.38 μm and the RMS of 0.27 μm, thereby validating the methodological efficacy.