The invention belongs to the technical field of research and development of medical products. The invention relates to a preparation method and application of a compound radix bupleuri preparation. The preparation method comprises the following steps: selecting 4-6g of high-quality radix bupleuri, 4-6g of medlar, 4-6g of spirulina, 4-6g of mushroom, 4-6g of kelp, 4-6g of cordate houttuyniae, 4-6gof ginseng, 2-3g of star anise, 2-3g of ginger, 2-3g of garlic, 2-3g of hawthorn, 2-3g of Chinese date and 9-12g of shrimp meal, washing, carrying out microwave drying, and grinding into 50-mesh powder; adding water to the powder, boiling to extract three times, merging the extracting solutions, and filtering to obtain the filtrate; and concentrating the filtrate into extract, uniformly mixing the extract and starch at a ratio of 1:4, granulating with a 10-mesh sieve, drying, and then sieving with a 14-mesh sieve, thus obtaining the compound radix bupleuri preparation. The product has the function of promoting liver functions and protein metabolism of golden carps and is beneficial to industrial production.