The wear of wiper inserts directly affects the finishing surface quality in multi-insert face milling. This research aims at monitoring the wear of wiper inserts, using 3D surface form as tool wear indicators. 3D surface height map of the face-milled surface is measured by a high definition metrology (HDM) instrument and converted into height-encoded and toolmark-straightened gray images. 3D surface form indicators, including entropy and contrast, are extracted from the converted images with a modified gray level co-occurrence matrix (GLCM) method. Meanwhile, the wear of wiper inserts is measured using a tool presetter and measuring machine without dismounting wiper inserts from the cutter. Experimental results indicate that entropy shows a strong correlation with average axial wear of the wiper edges and contrast reflects the evolution of axial offset between wiper inserts.