The invention provides a traditional Chinese medicine for treating metabolic syndrome and a preparation method thereof. The traditional Chinese medicine is prepared from eleven traditional Chinese medicines including codonopsis pilosula, Indian buead, cassia twig, bighead atractylodes rhizome, radix glycyrrhizae preparata, capillary wormwood, rhizoma pinellinae praeparata, rheum, rhizoma atractylodis, pearl barley and pericarpium citri reticulatae. The prescription sticks to pathological changes in the process of strictly controlling diets of patients with metabolic diseases, the medicines are reasonably compatible to have the effects of strengthening spleen, purging turbidity and warming phlegm-fluid retention. The traditional Chinese medicine is used for preventing and treating overweight/obesity and relative metabolic diseases, such as diabetes, hypertension, hyperlipidaemia, fatty liver diseases and the like. A preliminary clinical trial shows that the traditional Chinese medicine has the advantages of definite effect, quick action and no toxic or side effect, can greatly improve the capability of resisting hunger and the compliance for receiving diet control of the patients with metabolic syndrome, and is a good medicine for clinically treating metabolic syndrome.