To explore the impact of wildfire disease on phyllosphere microbial community diversity and function, 16S rRNA gene high-throughput sequencing technology was used to analyze the differences in the composition and diversity of phyllosphere prokaryotic microbial communities among plants with varying de-grees of wildfire disease. Additionally, PICRUSt software was employed to predict the gene function of phy-llosphere bacterial communities. The results revealed that, with the worsening of wildfire disease, both species richness and diversity of the leaf surface bacterial communities decreased significantly (P<0.01), and the distribution and composition of the leaf surface bacterial communities changed significantly (P<0.05). Cor-respondingly, pH in the culture medium increased, total phosphorus content decreased, and available potas-sium content first increased and then decreased. Furthermore, the correlations of the plant phyllosphere prokaryotic microbial community with immune system diseases, signaling molecules and interaction, exoge-nous biodegradation, and metabolism weakened with increasing disease severity. In conclusion, changes in the structure and function of leaf surface bacterial communities are closely related to the severity of wildfire disease in affected plants, and the disease can be relieved by decreasing pH and increasing total phosphorus and available potassium contents in the hydroponic solution.