Objective To investigate the effect of intermediate layer of flowable resin composite on the repair rate of patients with class Ⅱ cavities by hybrid resin composite restorations. Methods A total of 150 patients admitted to our hospital from March 2020 to March 2021 who simultaneously had two posterior teeth requiring class Ⅱ cavities by hybrid resin composite restorations were selected as the study subjects. They were randomly divided into a control group and an experimental group, with 75 patients in each group. The control group was filled with direct hybrid resin composite restorations, while the experimental group was filled with intermediate layer of flowable resin composite combined with hybrid resin composite restorations. The repair status and filling body detachment rate of the two groups were compared. Results The evaluation grades of appearance, edge coloring and edge suitability in the experimental group were lower than those in the control group, and the differences were statistically significant (P<0.05). There was no significant difference in the evaluation grade of glaze loss between the two groups (P>0.05). The total shedding rate of the filling body in the experimental group was lower than that in the control group, and the difference was statistically significant (P<0.05). Conclusion The intermediate layer of flowable resin composite has a high success rate in class Ⅱ cavities by hybrid resin composite restorations, and can effectively avoid the loss of the filling body, which is worthy of clinical application.