Urumqi No. 10 spring is located in the fracture zone of Willow ditch-Hongyanchi in southern Urumqi, and is one of the most important national key hydrological observation points. The spring water contains various geochemical elements, such as sulfide, methane, hydrogen, radon, sulfide, methane, carbon dioxide, helium, fluorine and mercury. Microbes living in the spring are intensely affected by hydro-geochemical changes caused by movements of the Earth's crust. The 24 solar terms, part of the Chinese traditional calendar, can accurately reflect changes in the Earth's climate, and the habitats of microorganisms also change with changes in the solar terms. In order to understand the changes in the structure of the bacterial community and diversity in Urumqi No. 10 spring with the 24 solar terms, spring water samples collected during each period of the 24 solar terms were analyzed by T-RFLP,and CCA analysis combined with hydro-chemical analysis of indicators in the spring was conducted. Diversity analysis shows that the Shannon index (H) of the spring bacterial communities has a large variation (from 1.088 to 3.003). Spring samples (from 'Beginning of Spring' to 'Grain Rain')show a significant fluctuating trend and reaches its lowest value in 'Waking of Insects' (1.088); in summer (from 'Beginning of Summer' to 'Greater Heat') and autumn (from 'Beginning of Autumn' to 'Frost's Descent'), the index shows similar increasing trends within the solar terms,while for winter (from 'Beginning of Winter' to 'Greater Cold'),the index remains at a low level (approximately 1.761). The changes in Simpson (D) and evenness index (E) were not significant throughout the 24 solar terms and the lowest value appeared in 'Waking of Insects'. Hierarchical cluster analysis shows that the bacterial community patterns for the spring water appear to cluster with the solar terms, reflecting the similarity of the sample community composition between solar terms within the same season. Adjacent seasons show mild diversity,indicating that the bacterial community composition has intraseasonal variations. T-RFLP analysis shows that there are 11 phyla in total: Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria and Fusobacteria are the main taxa (≥70%),and their proportions vary in each solar term; Cyanobacteria, Deinococcus-Thermus, Spirochaetes, Nitrospirae, Chlorobi,Tenericutes and some unknown taxa only appear in some of the solar terms,are present in low numbers,but they occupy a very important position in the community composition; Gram-positive bacteria are abundant in autumn and winter, while Gram-negative bacteria dominate in spring and summer. The existence of sulfur-oxidizing bacteria (Acidithiobacillus, Thiothrix) and sulfate-reducing bacteria (Desulfobacter, Desulfoluna) may be related to the high H_2S content in the spring. Hydrological chemical indicator analysis shows that conductivity, mercury, methane and hydrogen sulfide show the most variation. Of these indicators,fluorine and radon concentration can influence the dominant taxa,such as Bacteroidetes and Firmicutes,while Deinococcus is influenced by mercury concentration. These results indicate that the bacterial community in No.10 spring is influenced by changes in the 24 solar terms which in turn affect the hydrological chemical indicators.