Abstract: To explore the effects of two industrial processes on the flavor of plant-based compound milk. Headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with electronic nose and human sensory evaluation was used to analyze the differences of volatile flavor substances in the plant-based compound milk, that prepared by two soybean treatment technologies (oxygen separation grinding/enzyme inactivation with high temperature, grinding after enzyme inactivation) at different storage times (0, 90, 180 and 360 d) . The results of human and electronic senses showed that the milk, flower, fruit and cereal flavors of plant-based compound milk 1# and 2# gradually increased during storage, and the peculiar smell gradually weakened. Furthermore, compared to plant-based compound milk 2#, the plant-based compound milk 1# displayed better flavor and smaller change ranges in five flavor dimensions. A total of 46 volatile flavor components were detected by HS-SPME-GC-MS, including 15 alcohols, 7 aldehydes, 3 acids, 7 esters, 6 ketones and 8 other components. The results of principal component analysis showed that hexanol, 1-tetradecanol, 1-hexanol, pyridine, ethyl caproate, ethyl palmitate, 2-heptanone, 2-octanone, 2-acetylthiazole were the key factors affecting the flavor change of plant-based composite milk 1#, while 2,3 butanediol, n-hexanal, maltol, benzaldehyde, ethyl acetate, 3-ethyl-2,5-dimethylpyrazine were the key factors affecting the flavor change of plant-based composite milk 2# during storage. In conclusion, the plant-based compound milk prepared by oxygen seperation grinding/enzyme inactivation with high temperature had more pronounced aroma, and exhibited smaller changes during storage, which proved that the treatment technology of oxygen separation grinding/enzyme inactivation with high temperature displayed more advantages in improving flavor and flavor stability of plant-based compound milk.