Abstract: Objective To compare the postoperative sensitivity of deep caries treated with 3M light cured glass ionomer and DMG Ionosit-Baseliner. Methods A total of 84 posterior teeth with deep caries from 84 patients were randomly divided into two groups: 3M group and DMG group. 3M VitrebondTM light cured glass ionomer was used as liner material in Group 3M and Ionosit-Baseliner was used in Group DMG. After etching, both groups were filled with 3M FiltekTM Z350 nano composite resin. The sensitivity and the pain degree were evaluated and compared 1 day, 1 week, 1 month and 3 months after operation. Results There was no significant difference in the postoperative sensitivity and self-pain level between the two groups after 1 day, 1 week and 1 month （P>0.05）. Compared with group DMG, the incidence of sensitivity and self-pain level were lower in group 3M 3 months after operation（P<0.05）.Conclusions In posterior restorations, the light cured glass ionomer can reduce the incidence of postoperative sensitivity.