A preparation method of a purified vitelline freezing antibody for chickens infectious bursal disease is characterized in that: high purity antigens are adopted to vaccinate IBDV B87 to SPF chickens, then velvet urine, idiosome, velvet urine membrence are acquired, grinded, filtered and inactivated to antigens, and the steps are: producing immune eggs, collecting high immune egg, separating vitelline, diluting with distilled water, inactivating, extraction, decentering, inactivating, freezing and checking; the eggs is radiated by Co60 to kill viruses and bacterium, and finally froze by novel immuno-enhancer - Astragali Polysaccharoses and preserved under a temperature of 2-8 DEG C. Composite drugs for prevention and therapy are prepared by adopting the vitelline antibody for chickens infectious bursal disease as major components and cooperating with a novel immuno-enhancer, to decrease the jeopardy of the chicken breeding industry, and improve the living level of people and benefit mankind.