The invention discloses a grass carp feed and a preparation method thereof. The grass carp feed is prepared by the following raw materials in parts by weight: 15-20 parts of bean pulp, 10-15 parts of rapeseed dregs, 5-10 parts of fish meal, 4-8 parts of rice bran, 15-20 parts of wheat middling, 8-12 parts of bran, 1-2 parts of an additive, 3-6 parts of beer yeast, 5-10 parts of corn proteins, 2-4 parts of locust tree leaves, 1-3 parts of sesbania powder, 1-2 parts of citrus peel powder, 1-2 parts of monocalcium phosphate, 0.1-0.2 part of edible salt, 2-3 parts of linseed oil and 1-2 parts of dai-dai flower oil. The grass carp feed is complete and balanced in nutrition, high in food calling property, high in palatability, high in digestion rate and complete in nutrition indexes and has various nutritious components required by the growth of grass carps. After being fed with the feed, the grass carps grow fast, the disease resistance rate is obviously increased, and the survival rate can be increased to be over 95 percent; therefore, the breeding cost is greatly reduced, and high-quality intensive breeding is realized.