Abstract: In order to optimize the simmering process of bone broth for hotpot soup, a one-way analysis of bone ratio, material-liquid ratio, simmering time and simmering temperature was carried out using cow, pig and chicken bones as raw materials. The total nitrogen dissolution rate (TNDR) and sensory score of the bone broth were used as evaluation indexes. The Box-Behnken response surface methodology was employed to optimize the bone broth stewing process. Flavor analysis was conducted using an electronic nose and headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME-GC-MS) detection, with relative odor activity value (ROAV) combined with quantitative descriptive analysis (QDA) for flavor analysis, and orthogonal partial least squares-discriminant analysis (OPLS-DA) to correlate characteristic volatile organic compounds (VOCs) in bone broth from different raw materials with electronic nose data. The results showed that when the bone ratio (cow bone:pig bone:chicken bone) was 3:5:2, the material-liquid ratio was 1:4, the simmering time was 5 h, and the simmering temperature was 96 ℃ at atmospheric pressure, the TNDR of the bone broth under these conditions was the highest of 64.88%, and the organoleptic score was the highest of 86.45 points, and the bone broth was milky in color, with a strong fragrance and a mellow texture. Analyzed by electronic nose and HS-SPME-GC-MS, a total of 49 VOCs were detected in the four samples. The mixed bone broth yielded more benzene and amine flavor substances, and also increased the response values of W1S, W1W, W2S, and W2W, with a more significant flavor. There were 25 key VOCs specifically analyzed for ROAV≥1. A total of three key VOCs for the four samples were octanal, nonanal, and 5-hepten-2-one, 6-methyl-. There was a strong correlation by correlating the 12 characteristic VOCs with electronic nose signals for the substances with high flavor contribution to bone broth with ROAV≥1 and VIP≥1. This study can provide a basis for the industrial flavor optimization of bone broth in hotpot soup and the innovative application of modern cooking technology.