The invention relates to a duck virus hepatitis yolk antibody freeze-dried powder which comprises the following components: 85-88% of duck virus hepatitis yolk antibody, 0.8-1.0% of octanoic acid, 0.01-0.02% of thimerosal, 0.2-0.3% of formaldehyde, 4-5% of glucose, 1-2% of sorbic alcohol, 2-3% of glycine and 2-3% of mannitol. The freeze-dried powder has the advantages of long preservation time, high dissolving speed, high antibody titer and excellent biological activity, and more importantly, the purity of the antibody of the product is higher than that of the existing product on the market. At the same time, the invention also discloses a preparation method of the duck virus hepatitis yolk antibody freeze-dried powder, comprising the following steps: voluntarily separating strains in a disease prevalence area to prepare a vaccine, immunizing healthy dusks to obtain hyper-immune eggs, ad performing disinfection, acidification, octanoic acid treatment, refining extraction and purification, preparation, freezing and the like on the hyper-immune eggs to obtain the duck virus hepatitis yolk antibody freeze-dried powder. According to the preparation method in the application, a yolk solution is heated at the temperature of pasteurization when the acidification water treatment is carried out, so that not only is the disinfection purpose fulfilled, but also the recovery rate of the antibody and the clarity of the solution in the acidification treatment are increased, the prepared yolk antibody has the advantages of high biological activity, long antibody preservation time, titer reduction, lowered speed and the like.