Setting off fireworks during the Spring Festival are a popular traditional custom and recreational activity in China. Intensity of firecracker burning can quickly deteriorate air quality. Airborne bacteria are also important constituents of atmospheric particulate matter and contain many pathogens. However, few studies have reported variations in the bacterial community structure in PM_2.5 during firecracker burning. In this study, PM_2.5 samples were collected at four different sites in the city of Guilin during Spring Festival from February 4 to 8, 2019 and a high-throughput sequencing technology was used to investigate the variations of bacterial diversity and community structure in PM_2.5. The results revealed that Proteobacteria was the predominant bacterial phylum comprising 94.3% of the total sequences, followed by Firmicutes, Actinobacteria, Bacteroidetes, and Deinococcus-Thermus. At the genus level, the top five abundant genera accounted for 81.8% of the total sequences. The proportions of major genera (Cupriavidus, Sphingobium, Brevundimonas, Sphingomonas, and Pseudomonas) were apparently affected by firecracker burning. In particular, the relative abundance of Brevundimonas genus increased dramatically from 3.2 to 60.1% at the Huaqiaonongchang (HQ) sampling site during intense firework burning, while those of other major genera and potential pathogens detected including Pseudomonas, Acinetobacter, and Serratia decreased. In addition, compared with the normal condition, the number of operational taxonomic units and the diversity and richness of microorganisms in PM_2.5 samples decreased apparently. Pearson correlation results also revealed that they were negatively correlated with the NO₂, SO₂, and PM_2.5 concentrations.