Abstract: Objective: To study the condition of dental caries in Uighur children in southern Xinjiang and analyze the reasons of high incidence of caries in microbiology.Methods: Caries and filling rate of 296 Uygur children aged 3-5 in 5 company kindergartens in southen xinjiang were randomly selected.The microbiological community structure and diversity of oral cavity in children were analyzed by illumina misequencing platform.Results: Tooth decay rate was 83.4%, average caries was 3.07±3.22, and supplementary filling rate was 2.07%.The tooth decay rate and average caries of 5 year old group were higher than those of 3 year old group.There was no significant difference between the rate of caries and the average of caries in children with different gender.The dental plaque of two groups was various.There were 98 outs, belongs to12 phylum, 18 classes, 25 orders, 34 families, and 60 genus.Streptococcaceae, porphyromonadaceae, fusobacteria, veillonellaceae, and peptostreptococcaceae were richer in high caries.Conclusion: The incidence of dental caries in Uygur children in southern Xinjiang is higher than the domestic average, and it is necessary to strengthen the input of oral resources in southern Xinjiang.There are some differences in the structure of oral microorganism community between caries and non-caries.The effects of streptococcaceae, porphyromonadaceae, fusobacteria, veillonellaceae, and peptostreptococcaceae on caries development need to be further studied.

Key words: Caries, Dental plaque, Microbial community structure, 16S rRNA, High-throughput sequencing