The invention discloses a Dai medicated diet soup capable of tonifying spleen, helping digestion and invigorating stomach and a preparation method thereof. The Dai medicated diet soup comprises the raw materials of, by mass, 1000 parts of food materials, 20 to 50 parts of processed polygonatum kingianum, 5 to 10 parts of fructus amomi, 0 to 5 parts of amomum tsao-ko kernel, 15 to 20 parts of radixpseudostellariae, 0 to 50 parts of Chinese yam, 5 to 20 parts of amomum kravanh root, 10 to 30 parts of fennel nutmeg root, 0 to 50 parts of fennel root fresh product, 0 to 20 parts of fried endothelium corneum gigeriae galli, 0 to 10 parts of valeriana jatamansi jones and 0 to 10 parts of amomum cardamomum. The Dai medicated diet soup capable of tonifying spleen, helping digestion and invigorating stomach can achieve the effects of tonifying qi, nourishing yin, tonifying spleen, moistening lung, resolving dampness, harmonizing stomach, stopping diarrhea, regulating qi and the like, and can achieve a remarkable regulating effect on symptoms such as weakness of spleen and stomach, inappetence, stomach cold, nausea, abdominal distension, dyspepsia and the like.