Seasoning packets, which are essential for pre-cooked Xiongzhang tofu dishes, contain odor substances that are crucial for providing food aromas because of their low molecular weights, boiling points, and volatilities. Identifying these volatile substances is crucial; however, the impact of sterilization on these compounds is not well understood. Therefore, we explored the effect of thermal sterilization on the volatile substance content of Xiongzhang tofu seasoning packets. Three different sterilization treatments were investigated using sensory evaluation, electronic noses, and gas chromatography-mass spectrometry (GC-MS) combined with microbial indicators, orthogonal partial least squares discriminant analysis, the odor activity value (OAV), and differential heat maps. Heat sterilization enhanced flavor richness and preference scores, with the microbial content meeting national standards. GC-MS analysis revealed that pasteurized samples had high similarity with non-sterilized samples, whereas high-temperature/high-pressure sterilized samples showed significant differences. OAV analysis revealed dominant fruity, floral, and spicy aromas, with significant differences in the characteristic compounds among samples. The main characteristic differences among the three treatments were attributed to compounds including (methoxymethyl) ethylene oxide, 2,3-butanediol, epoxypropane, methoxyacetone, methyl thioether, and formic acid. High-temperature/high-pressure sterilization may have facilitated the release of sulfur-containing substances. This study enriches our understanding of the impacts of thermal sterilization of the volatile substance content of seasoning packets in pre-cooked dishes.