Gastrointestinal bacteria contribute to host health by maintaining homeostasis, increasing digestive efficiency, and facilitating the development of the immune system. Host genetics, diets, ages and environments strongly influence the composition of the gut microbiota. However, changes in microbial community structure with host age remain poorly understood. In this study, collected 2 adults and 3 chicks Bar-headed Geese (Anser indicus) cloacal samples, extract total DNA samples, and using 16S rRNA high-throughput sequencing, analysis and comparison the difference of composition and flora structure. According to analysis the intestinal microflora of adult and chick of bar-headed geese, to observed the dynamic changes of different age stage of bird intestinal microflora. A total of 9 different bacterial phyla were identified in the cloacal microbiota of chicks (Fig. 1a). The results showed that Fusobacteria predominated (48.29%) among chicks followed by Firmicutes (22.21%), Proteobacteria (22.07%), Actinobacteria (5.02%) and Tenericutes (1.93%) (Table 2). A total of 17 different bacterial phyla were identified in the cloacal microbiota of adults (Fig. 1a). The top 5 most abundant phyla identified were: Proteobacteria (64.69%), Firmicutes (23.92%), Cyanobacteria (8.48%), Actinobacteria (1.43%) and Fusobacteria (0.56%) (Table 2). At the genus level, the sequences from the samples represented 18 and 24 genera in chicks and adults, respectively (Fig. 1b). We employed Chao1 index and observed species curve to estimate the alpha diversity of the chicks and adults cloacal samples. These results suggested that the diversity of the cloacal microbiota of adult bar-headed geese was higher than in chicks. Analyses based on Bray-Curtis distances revealed strong clustering of the samples by age (Fig. 3a). At the OTU level, there were 186 OTUs shared between the samples from adults and chicks, whereas the other 640 OTUs and 90 OTUs, were specific to the adults and chicks, respectively (Fig. 3b). These results indicated that majority of OTUs (67.39%) presented in the chicks were also presented in the adults. The top 25 most abundant OTUs at the genus level shared by both adults and chicks were shown in Fig. 4. This preliminary study would be valuable for future investigations of the sequential changes in gut microbiota composition with age in birds.