The present invention provides a duck viral hepatitis bivalent yolk antibody and a preparation method thereof, wherein the bivalent yolk antibody comprises a duck viral hepatitis DHAV-1 type antibody and a duck viral hepatitis DHAV-3 type antibody. The preparation method comprises: (1) adopting a duck viral hepatitis DHAV-1 type strain and a duck viral hepatitis DHAV-3 type strain to respectively vaccinate SPF chicken embryo and susceptible duck embryo, harvesting allantoic fluid, mixing the harvested virus liquids according to a certain ratio, carrying out formaldehyde inactivation, and preparing a vaccine; (2) adopting the vaccine to immunize laying hens, sampling after immunization to determine whether the neutralizing titer of the anti-DHAV-1 type antigen antibody and the anti-DHAV-3 type antigen antibody in the chicken hyperimmune egg yolk is more than or equal to 1:8192, and collecting the hyperimmune egg of the chicken; and (3) disinfecting the eggshell of the hyperimmune egg, collecting the egg yolk, adding the equal volume of distilled water, uniformly stirring and mixing, carrying out low temperature pasteurization inactivation, adopting an acidification distilled water method to purify, adopting an octanoic acid method to purify, and carrying out micro-filtration and ultra-filtration. The duck viral hepatitis bivalent yolk antibody has characteristics of low cost and high titer, and can be provided for effectively controlling duck viral hepatitis caused by DHAV-1 and DHAV-3 so as to obtain significant social benefits.