Abstract：Objective: To study the diversity and abundance of nasopharyngeal microbial flora in children with adenoid hypertrophy.Methods: the clinical data of 30 children with adenoid hypertrophy, 18 males and 12 females, who were treated in the Department of Otolaryngology, Hunan People's Hospital from June 2021 to June 2022, were collected, the average age was 6.6 years. The adenoidal surface secretions were collected for analysis of the nasopharyngeal microbiota using the 16S ribosomal RNA method, followed by sequencing for bioinformatics analysis (BMkCloud, www.biocloud.net ) . Results: the species diversity and abundance of nasopharyngeal microbial florawere changed in children with adenoid hypertrophy. In the severe adenoid hypertrophy group, the proportion of Haemophilus and Moraxella was significantly higher (40.19% and 24.93%), and streptococcus was significantly lower (14.66%). Conclusion: the bacterial abundance of nasopharyngeal species changes in children with adenoidal hypertrophy. The increased abundance of Haemophilus, Moraxella, and decreased abundance of Streptococcus may lead to adenoidal hypertrophy. It is helpful to understand the microbial mechanism of adenoid hypertrophy in clinic.