The 120-day fermentation process and microbial community changes in Ciba chili paste were investigated. Dynamic changes in total acid, pH, electronic nose response values, and viable microbial counts during the fermentation cycle were analyzed. Metagenomic analysis was employed to elucidate microbial community succession. The results showed that pH decreased from 4.73 to 4.11, whereas total acid content increased from 8.28 to 13.53 g•kg-1 during fermentation. The response values of all electronic nose sensors decreased significantly after fermentation. Lactic acid bacteria, bacteria, and yeast counts increased to 5.45, 5.51, and 2.79 lg CFU/g, respectively, during the middle stage of fermentation, whereas the mold count peaked at 2.16 lg CFU/g in early-stage fermentation. In the final stage, lactic acid bacteria and bacteria counts decreased to 5.21 and 5.35 lg CFU/g, respectively, and stabilized, whereas yeast and mold counts dropped to <10 CFU/g. Based on α-diversity analysis, bacteria were the dominant microbial community in Ciba chili paste fermentation; Staphylococcus, Leuconostoc, Lactiplantibacillus, Bacillus, and Weissella were dominant in the early stage and were succeeded by Fructilactobacillus in the middle-late stage. The fungal community was dominated by Zygosaccharomyces, Aspergillus, Starmerella, and Wickerhamiella, which were collectively involved in the fermentation process. These findings provide a theoretical basis for optimizing Ciba chili paste production and developing a fermented hotpot base.