The structural characteristic that O-glycan sugars prefer to bind to the regions forming β-strand structures is reported in this paper. While N-acetylglucosamine (GlcNAc) and mannose (Man) modification sites were contained in β-strand structures, fucose (Fuc) modification sites were found on β-strand and coil structures close to the β-strand structures. In particular, most Fuc modifications in EGF-like domains were identified on the edge of β-strand structures. Glycosyltransferases is thought to recognize motif residues in β-strand structures. The finding in this study that O-glycosylation preferred β-conformation and coil structures can be applied for the development of prediction methods and be useful to improve prediction accuracy.