The invention relates to a pig feed additive and its preparation method and an application, and relates to the field of feed additive. The pig feed additive is prepared from, by weight, 1-5 parts of jujube date polysaccharide, 1-2 parts of composite probiotics, 6-10 parts of plant extract, 6-10 parts of pyridoxine hydrochloride, 12-20 parts of Vitamin C, 18-25 parts of Vitamin E, and 28-56 parts of carrier matrix. The preparation method includes steps of screening and mixing the jujube date polysaccharide with the plant extractive, adding other components to fully and evenly mix the raw materials. The preparation method is simple in operation and good in controllability. Compared with the prior art, the pig feed additive can be added to the basal diet of a pig; every component is in synergistic interaction, and can effectively promote the animal growth; the weight increasing speed is quick, the feed utilization rate is improved, and the meat quality is obviously improved; besides, thetenderness and flavor are increased; the pig feed additive is free from drug residue, thus the meat product is safer and better in quality.