The invention relates to a micro-granule feed and a preparation method thereof. The shape of the micro-granule feed is selected from one or more of a cylinder, a triangular prism, a cuboid and a shape with an irregular cross section, the diameter or the equivalent circle diameter of the micro-granule feed is 0.5-2.5mm, and the length of the micro-granule feed is 3-5 times of the diameter. The micro-granule feed is prepared from the following raw materials in percentage by weight: 60-70% of fermented raw materials, 1-4% of soybean oil, 2-6% of fish meal, 15-25% of whey powder, 3-9% of plasma protein powder, 2-3% of a premix and 0.3-0.8% of a liquid additive. The preparation method of the micro-granule feed comprises the following steps of preparing the fermented raw materials, performing heating treatment, performing granulation, performing crushing, performing screening, and spraying the liquid additive. Compared with the prior art, the micro-granule feed disclosed by the invention can effectively promote appetite, increase the food consumption and the daily gain, reduce diseases of diarrhea and the like, reduce the feed conversion rate and improve the growth properties of animals.