In an ultraprecision turning process for small-diameter optical aspheric workpieces, tool-profile errors induce mid-frequency errors in the workpiece profile, limiting further improvements in precision. In this study, an XZB three-axis linkage ultraprecision machining method is proposed, and the effects of tool-center errors are analyzed. To address residual errors in Z-direction profile-error compensation, a workpiece normal-profile-error compensation method is proposed. After XZB three-axis linkage turning and compensation, the workpiece profile error (PV) reaches 0.086 μm, surpassing the precision of XZ two-axis machining, and mid-frequency errors are reduced. Compared with Z-direction profile-error compensation, which results in a profile error of 0.092 μm, normal-profile-error compensation reduces PV to 0.047 μm, considerably improving aspheric accuracy. Experimental results demonstrate that XZB three-axis linkage machining significantly improves the aspheric workpiece profile, enhancing both its accuracy and surface quality. This method reduces mid-frequency errors, and the subsequent application of normal-profile-error compensation further refines the profile, achieving higher overall accuracy.