Abstract: The frequency of post-fire debris flow events in burned areas has increased significantly following wildfires. In different bedrock class regions, post-fire debris flow has significant differences in the formation conditions, initiation modes, and evolution characteristics. There is currently a research gap regarding the development characteristics of post-wildfire debris flows in various rock types within the domestic context. This study follows the 12 forest fires in different lithological zones in the Sichuan province of China, located on the eastern edge of the Hengduan Mountains, from 2014 to 2021, through a tracking investigation and field test at different stages in burned areas. The geological and environmental conditions of the burned area, the discrepancy in soil properties, the material sources of debris flow, the material erosion of debris flow initiation processes, and characteristics of scouring siltation of post-fire debris flow were identified. Then the variability of post-fire debris flow evolution characteristics in different lithological zones was revealed. The results indicate that the burned areas in the metamorphic rock area are characterized by the greatest changes in soil properties, thicker ash sediment layer (3-7cm), and the highest frequency and largest scale of post-fire debris flow. The total volume of the first rainy season post-fire debris flow in metamorphic areas is four to eight times larger than in sedimentary rocks and four to six times larger than in igneous areas. In contrast, sedimentary and igneous rock areas show less pronounced changes in soil properties, thinner ash layers (1−3 cm), and comparatively smaller debris flow events. These findings advance the understanding of post-fire debris flow and provide effectively guidance for the design of post-fire debris flow prevention and control projects in different bedrock class regions.