The invention discloses a preparation method of roasted yam spice, which comprises washing and peeling, crushing and beating, decompression filtration, yeast fermentation, high-temperature baking and supercritical CO 2 Extraction and other steps, after cleaning and peeling, crushing and beating, vacuum filtration, and yeast fermentation, the foot plantain potatoes are baked at a temperature of 100-220°C, and then passed through supercritical CO 2 Just extract. The roasted yam spice prepared by the method of the present invention is evenly sprayed on the shredded tobacco in the cigarette feeding process, highlighting the "roasted fragrance" aroma of the cigarette, thereby improving its smoking quality and sensory comfort, significantly improving the cigarette aroma, improving the aftertaste, and stimulating The smoke and miscellaneous gas are also greatly reduced, and can be used as a new type of tobacco flavor in the whole industry. In addition, the product of the invention has low cost, simple process and high safety.