Abstract: To provide a theoretical basis for the effects of functional oligosaccharides on the oral microorganisms, the efficacy of several oligosaccharides on the growth, acid production, adherence and biofilm formation of three cariogenic bacteria including Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum were investigated. The three cariogenic bacteria were cultured in TSB medium with xylooligosaccharides, galactooligosaccharides, fructooligosaccharide and isomaltooligosaccharide at the different concentrations, and the absorbance, pH, adhesiveness as well as biofilm formation inhibitory activity were measured for 48 h. The effects of different oligosaccharides on bacterial growth, acid production and adhesion were compared and analyzed. The results showed that four oligosaccharides had inhibitory effects on three kinds of cariogenic bacteria, and xylooligosaccharide had the highest inhibitory effect. Xylo-oligosaccharides and galactooligosaccharides at 0.5% concentration could significantly inhibit the acid production of the three cariogenic bacteria. Compared with xylitol and other oligosaccharides, the inhibition rate of xylo-oligosaccharide on the three pathogens was 60% higher when the xylo-oligosaccharide concentration was more than 5%. The adhesion rates of the four oligosaccharides at 7% concentration to the three cariogenic bacteria were all less than 50%. When the concentration of galactooligosaccharides and xylo-oligosaccharide was greater than 5%, the biofilm formation of the three cariogenic bacteria was inhibited well. By comparison with sorbitol, the combination use of xylo-oligosaccharide, xylitol, galactooligosaccharides had more obvious inhibition on the growth of the three pathogenic bacteria.