The invention provides a mandarin fish fodder and a preparation method thereof. The mandarin fish fodder is prepared from the following raw materials: cottonseed cake flour, rye bran flour, soybean meal, rape seed cake, chironomidae larvae powder, small carp flour, chicken intestine flour, herba houttuyniae, hemiculter leucisculus flour, escargots flour, yeast powder, meat and bone meal, radish leaf, rheum officinale, saponin, felwort, calcium phosphate, inorganic salt, microecologics and phagostimulant. The preparation method comprises the following steps of (1) after uniformly mixing the cottonseed cake flour, the rye bran flour, the soybean meal and the rape seed cake according to proportion, crushing the mixture into powder; (2) cutting the herba houttuyniae and the radish leaf for later use; (3) after uniformly mixing the rheum officinale, the saponin and the felwort, adding an appropriate amount of water to decoct for 20 to 30 minutes, removing dregs and reserving juice; and (4) mixing the left components except the calcium phosphate and the inorganic salt with the mixtures obtained in the steps (1), (2) and (3), controlling water, adding the calcium phosphate and the inorganic salt, and after uniformly stirring, pelletizing. By the fodder, growth of mandarin fishes can be quickened, and the fodder utilization rate is improved.