The invention discloses a formula and processing method of a feed capable of improving immune properties of animals. The feed is prepared from the following raw materials in parts by weight: corn, bran, bean cakes, bone meal, conch meal, cottonseed cakes, rape seed cakes, a trace element additive, silkworm chrysalis meal, fish meal, stone powder, blood powder, mulberry leaves, cortex moutan, giantknotweed rhizomes, mango leaf extractum, roots, stems and fruits of vitis flexuosa, fern, grenateleaf heteropappus herbs, onychium japonicum herbs, dioscorea subcalva tubers, radix pedicularis henryi / radix pedicularis longicaulis, auricularia polytricha, alternanthera philoxeroides herbs and table salt. The kinds of the materials and the content of materials are selected, and particularly the mango leaf extractum is determined, so that nutrient substances in the feed are reasonably matched, the feed is suitable for digestion and absorption by pigs, the increase speed of the pigs is significantly increased, besides, the immunity of the pigs is also enhanced, and the food safety of pork is improved. Besides, the invention discloses the processing method of the feed. The processing method comprises the following steps of preparing the components in parts by weight, performing crushing, performing blending, performing granulation and performing packaging. The processing efficiency is high.