The invention discloses a selenium-rich pig feed. The selenium-rich pig feed comprises selenium-rich raw materials and main materials, wherein the selenium-rich raw materials are prepared from the following raw materials: selenium-rich corn, selenium-rich alfalfa, selenium-rich day lilies, selenium-rich astragalus membranaceus, selenium-rich gynostemma pentaphyllum, selenium-rich milk vetch, and selenium-rich sweet potato leaves; the main materials are prepared from the following raw materials: soybean meal, peanut meal, fish meal, bone meal, middling, soybean oil, table salt, lysine, methionine, valine, complex vitamins, choline chloride, a mycotoxin adsorbent and complex trace elements. The invention further discloses a preparation method of the selenium-rich pig feed. The preparation method comprises the steps of crushing, mixing and the like. The invention further discloses an application method of the selenium-rich pig feed. Before 40-80 days when porkers become full-grown and are ready for slaughter, the selenium-rich pig feed is fed according to the normal feeding number of pigs. According to the selenium-rich pig feed disclosed by the invention, selenium-rich Chinese herbal medicine ingredients are added, so that the nutrition is balanced, the immunity of the pigs can be improved, and the selenium content of pork is increased. The preparation method is simple. The selenium-rich pig feed disclosed by the invention is scientific and reasonable in application method, and the breeding benefits of the pigs can be increased.