Objective To evaluate the impact of zirconia ceramic brackets on the adhesion of Streptococcus mutans . Methods In the experiment, 18 brackets were collected, including 9 zirconia ceramic brackets in the observation group and 9 alumina ceramic brackets in the control group. After the brackets in both groups were cultured in the brain heart infusion broth with saliva for 72 hours, TaqMan probe method of qRT-PCR was applied to analyze the amount of Streptococcus mutans and total bacteria, thus the composition ratio of Streptococcus mutans was calculated. A comparative study in the composition ratio of bacteria was carried out between the two groups. Results There was no statistical difference in composition ratio of Streptococcus mutans to total bacteria between the two groups (P > 0.05), either in the amount of Streptococcus mutans or total bacteria adhered to the brackets between the two groups (P > 0.05). Conclusions The adhesion of Streptococcus mutans and total bacteria to zirconia ceramic brackets is of no obvious difference from that to alumina ceramic brackets, which needs further clinical research.