A multisegment stitching method is proposed to get the profile of steep aspheric surfaces with even 90-deg edge slope. The profile is divided into several segments overlapping each other, and the segments are measured with a high-precision stylus profilometer one by one. Then an iterative algorithm is used to stitch all of the segments together, based on the minimization of inconsistency among the overlapping regions. A convex hyperbolic surface is measured with three-segment stitching, and the result is approved by full-profile testing. We also demonstrate the method with a steep elliptical surface, measured and stitched by five segments. Finally, discussions are given on the error introduced by sagittal displacement of the segments.