The invention discloses meal replacement powder for improving phlegm-dampness constitution, which is prepared from, by weight, 2-4 parts of lotus leaves, 5-8 parts of red beans, 1-3 parts of poria cocos, 1-3 parts of mint, 4-6 parts of black soybeans, 1-3 part of raw hawthorns, 8-12 parts of husked sorghum, 1 part of platycodon grandiflorum, 1 part of kudzu vine roots and 1 part of cinnamon. A preparation method comprises the steps: S1, washing the raw materials, and then executing the step S2; S2, weighing 1 part of platycodon grandiflorum, adding 9 parts of water, executing soaking for 30 minutes, executing decoction with medium fire for 30 minutes, and taking and stir-frying 5 parts of medicinal juice obtained after decoction and 1-3 parts of mint with small fire for 5-10 minutes; weighing 1 part of kudzu vine roots, adding 9 parts of water, executing soaking for 30 minutes, executing decoction with medium fire for 30 minutes, and taking 5 parts of medicinal juice obtained after decoction and 24 parts of lotus leaves, 5 parts of red beans and executing stir-frying with small fire for 5-10 minutes. The powder integrates medicines and foods, can be taken for a long time, does nothave toxic or side effects, not only can promote hydration and dampness, but also can invigorate the spleen, has the effect of eliminating phlegm, has the very good effect on dredging a waterway, gives consideration to upper, middle and lower jiao, and is beneficial to the lung, spleen and kidney.