The wastewater discharged from the sewage treatment plant has a greater impact on the river microbial community. In order to understand the degree of its influence and the response of microbial communities to environmental factors, 16S rRNA technology, bioinformatics analysis and statistical analysis were used to analyze the evolution characteristics of microbial communities in the sediments of the Taiping River and the response law on the wastewater from the sixth and seventh sewage treatment plants in Xi’an. The study found that the abundance of the microbial community gradually increased with the increase of the distance from the drainage outlet. Cyanobacteria was the biomarker in the microbial community of the Taiping River, and α-proteobacteria (alphaproteobacteria) was a key species for the community function of the Taiping River. Microbial community had the most significant response to dissolved oxygen (DO), temperature and salinity. The change of microbial community structure in the sediments of receiving rivers can reflect the impact of wastewater discharged from sewage treatment plants on river water quality, and then characterize the health of river ecosystem.