The present invention discloses compound tea having a weight losing effect and a preparation method thereof. The compound tea comprises dietary fibers, mogroside, a white kidney bean extract, a coix seed extract, a lotus leaf extract, a black tea extract, Wuling power (consisting of polyporus umbellatus, poria cocos, rhizoma atractylodis macrocephalae, rhizoma alismatis and cassia twigs) and plant protein powder. The method is as follows: the dietary fibers, mogroside, white kidney bean extract, coix seed extract, lotus leaf extract, black tea extract, Wuling powder and vegetable protein powder are sufficiently dissolved using water, the dissolved materials are homogenized, the homogenized materials are filtered, a filtrate is concentrated in vacuum, the concentrated material is sterilized, the sterilized material is freeze-dried, and the freeze-dried material is subjected to a granule separating to obtain the finished product. The compound tea is excellent in color, fragrance and taste, instant after brewing, relatively good in uniformity and stability, and not layered after tea soup is put still within 24 hours. Experiments show that a regular drinking of the compound tea brewed tea soup can enable weights of patients at 84% or more to restore to healthy levels. Besides, after a stopping of the drinking, body weights do not show obvious rebound within half a year. The compound tea is simple and stable in technology, low in costs and suitable for large-scale productions.