Objective To investigate the distribution characteristics of nasal cavity and maxillary sinus microbiota in aged patients with chronic maxillary sinusitis.Methods A total of 15 aged patients with chronic unilateral maxillary sinusitis who received surgical treatment between January 2017 to June 2018 in Beijing Hospital were enrolled and analyzed retrospectively.Their lavage samples from nasal cavity(N)and maxillary sinus(M)were collected and the samples were labeled according to the location(N and M groups,n=15 each).The high-throughput sequencing was used for sequencing all bacterial 16S rRNA genes in the samples.The composition of nasal cavity and maxillary sinus microbial communities was obtained,and the distribution features of nasal cavity and maxillary sinus microbiota were analyzed.Results A total of 8 bacterial phyla and 34 bacterial genera were found in nasal cavity and maxillary sinus microbiota.The most widely distributed phyla in nasal and sinus groups were Bacteroidetes,Fusobacteria,Frimicutes,Spirochaetes and Proteobacteria.The abundance of Bacteroidetes was higher in group M(60.0 ％,51 762/86 301)than in group N(42.9 ％,37 999/88 576)with statistically significant difference(P ＜0.05).The most widely distributed bacteria genera were Prevotella,Fusobacterium,Alloprevotella,Treponema,Parvimonas,Streptococcus,Filifactor,Phocaeicola,Campylobacter,Prevotella-7 and Lentimicrobiaceae.The abundance of Prevotella was higher in group M(47.7％,41 252/86 414)than in group N(33.5％,29 680/88 598) with statistically significant difference(P ＜ 0.05).Conclusions In the aged patients with chronic maxillary sinusitis,the distribution of bacteria in the nasal cavity and maxillary sinus is partly consistent.The abundance of the anaerobes distribution is higher in maxillary sinus than in nasal cavity in aged patients with chronic maxillary sinusitis.