The invention provides a traditional Chinese medicine microbial ecological agent for preventing and treating infectious bursal disease of chicken and a preparation method thereof. The preparation method comprises the following steps: adding water to radix isatidis, honeysuckle, forsythia, folium isatidis, humulus scandens, radix scutellariae, dangshen, ageratum, plantain, astragalus membranaceus, angelica sinensis and liquorice, boiling by using high heat, preserving heat for 30-60 minutes by using slow fire, cooling, filtering, collecting filtrate, adding white sugar, boiling, cooling to a normal temperature, then inoculating lactobacillus, zygosaccharomyces bailii and acetobacter xylinum, and fermenting for 3-7 days so as to obtain the microbial ecological agent. After the microbial ecological agent is diluted proportionally, the diluted microbial ecological agent is directly drunk by chicken. The traditional Chinese medicine microbial ecological agent provided by the invention has the effects of resisting viruses, inducing interferon, increasing the quantity of effective microbial communities in intestinal tracts, boosting immunity and improving disease resistance of chickens without toxic or side effects and the like; the preparation method is simple, convenient to use and high in viable bacteria content and has no residues. The traditional Chinese medicine microbial ecological agent provided by the invention has a certain curative effect on infectious bronchitis and henpox and relatively good market prospect.