The invention discloses a feed additive for improving fat meat qualities of slaughter pigs and a preparation technology thereof. The feed additive for improving the fat meat qualities of the slaughter pigs is prepared form the following raw materials in percentage by weight: 16-18% of astragalus polysaccharides, 25-28% of tremella polysaccharides, 14-15% of tea polyphenols, 17-18% of flax seed oil, 0.6-0.7% of betaine, 0.4-0.6% of choline, 4.5-6% of conjugated linoleic acid, 2.5-5% of lysine, 3-4.5% of threonine, 3-4% of arginine, 1-1.2% of vitamin A, 4-6% of vitamin C, 0.7-1% of vitamin E, 0.3-0.5% of folic acid, 0.3-0.5 of biotin, 0.25-0.3% of selenium yeast, 0.25-0.3% of chrome yeast, 0.05-0.1% of iron, 0.05-0.2% of zinc, 0.2-0.4% of manganese and 0.3-0.5% of copper. The invention has the following beneficial effects: the feed additive disclosed by the invention is added with many ingredients which are beneficial for improving the meat qualities, and the feed additive is enriched in vitamins and trace elements which are required during growth cycles of the pigs; moreover, the feed additive has the effects of promoting animal appetite, resisting stress, improving pork qualities and so on.