Objective To observe sclerotic dentin bonding interfacial nanoleakage used total-etching system and self-etching system by confocal laser scanning microscope（CLSM）. Methods 12 maxillary bicuspids with non-caries, natural cervical sclerotic lesions were divided into three groups. Artifically prepared wedge-shaped lesions were made in 12 sound maxillary bicuspids and divided into three groups as controls. Three kinds of dentin bonding agents, Single Bond（SB）, Clearfil SE Bond（CB） and Xeno Ⅲ（XB）, were applied on the surface of the wedge-shaped lesion dentins according to the manufacturer′s instruction. The apical foramens were occluded with self -curing resin. Six specimen groups were individually exposed to 0.1% rhodamine B isothiocyanate in 50% alcohol solutions for 24 h. Then the teeth were section using slow saw and observed the specimens under CLSM. Results Two-way ANVOA revealed significant influence of both type of the dentin substrate and the adhesive systems tested on the lengths of the dye-penetrated pathways, representing the amount of nanoleakage（P0.05）. There was no statistical significance in the amount of nanoleakage in normal dentin and sclerotic dentin using SB（P=0.148）. In CB and XB, the amounts of nanoleakage in normal dentin were higher than in sclerotic dentin（P
