Abstract： Objective： To investigate the effects of rubusoside on the growth and cariogenicity of streptococcus mutans (S.mutans)， and to provide a new idea for the prevention and treatment of dental caries. Methods：S.mutans was treated and cultured in a constant temperature and anaerobic environment， and the minimum inhibitory concentration (MIC) was determined by the OD value of bacterial solution，and 0.625，1.25，2.5 and 5 mg/mL were determined as working concentrations. pH，hydrophobicity，adhesion， biosynthesis of water-insoluble polysaccharide (WIG) and glucosyltransferase (GTF) activity indexes including total protein content，reducing sugar content，GTF activity and specific activity of S.mutans cultured with rubusoside or xylitol at working concentration were detected and compared. Results ： The growth of S.mutans was significantly inhibited by rubusoside at concentration≥0.625 mg/mL ， and its MIC was 10 mg/mL. Compared with the control group and xylitol group，acid production，hydrophobicity，adhesion， WIG，reducing sugar content，GTF activity and specific activity of S.mutans were decreased after addition of rubusoside， and the total protein content was increased(P＜0.05). Compared with the control group， xylitol group had obvious inhibitory effects on hydrophobic rate， adhesion and WIG， reducing sugar content，enzyme activity and specific activity of S.mutans only when the concentration was ≥ 2.5 mg/mL (P＜0.05)， but had no significant effects on acid- producing capacity and total protein content (P＞0.05). Conclusion： Rubusoside can effectively inhibit the growth， acid production， adhesion， WIG synthesis and GTF activity of S.mutans，which is better than xylitol at the same concentration.