Abstract: Using kale, Mesembryanthemum crystallinum and purple carrot as the main raw materials, and angel Lactobacillus as fermentation strains, the purple carrot compound fermented beverage was prepared. Orthogonal experiment was used to optimize the sugar addition, inoculum amount, fermentation temperature and fermentation time. Results showed that the optimal sugar addition of the fermented vegetable beverage was 7%, the lactic acid bacteria inoculation amount was 5‰, the fermentation temperature was 41 ℃, the fermentation time was 38 h. The final compound fermented beverage with moderate sour and sweetness taste, and bright red color was obtained. And the total sugar was 0.21 g/L, the total acid was 0.38 g/L, the dietary fiber content was 0.41 g/L, the number of Lactobacillus was 7.42×10⁷ CFU/g, the sensory score was 93.3. A total of 71 volatile flavor substances were detected, mainly ketones and aldehydes, followed by alcohols, acids, esters and other compounds. Among them, the highest concentrations of geranylacetone, acetic acid and (2E)-2-decenal were 15.60%, 13.14% and 6.40%, respectively, which were the main sources of fermented beverage flavor. This study provides new ideas for the development of vegetable beverages and provides a reference for the further development of agricultural and sideline products.