The invention relates to a high-nutrition feed additive for preventing feed fat oxidization as well as a preparation method and application thereof, and belongs to the field of feed. The feed additiveis prepared from artemisia scoparia extracts, potassium chloride, calcium chloride, lysine, arginine, organic acid and the balance of carriers. The feed additive does not havehas no harmful residuesor drug resistance; after the matched use of each all the raw material ingredients, the effect is good and stable. The preparation method comprises the following steps of each all the raw material isare mixed according to the mixture ratio; simplicity and high speed are realized; the condition controllability is high; the feed stability is high. When the feed additive is added into the pig feed,the oxidization of fat compounds, protein and the like can be effectively prevented and reduced; the feed anti-oxidization capability is enhanced; the feed storage period is prolonged; the feed nutrition ingredient stability is improved; in addition, the pig intestinal tract health can be effectively improved; the diarrhea rate is reduced; the immunity is enhanced; the pig growth is promoted.