The invention relates to duplex egg yolk antibody freeze-drying powder for duck virus hepatitis and duck plague, which comprises each following component according to weight percent: 30 to 60 percent of egg yolk antibody for duck plague, 30 to 55 percent of egg yolk antibody for duck virus hepatitis, 0.2 to 0.3 percent of formaldehyde, 0.01 to 0.02 percent of thiomersalate, 4 to 5 percent of glucose, 1 to 2 percent of sorbitol, 2 to 3 percent of glycocoll and 2 to 3 percent of mannitol. The invention discloses a preparation method of the duplex egg yolk antibody freeze-drying powder for the duck virus hepatitis and the duck plague simultaneously, which comprises the following steps of: separating a strain, preparing a vaccine, immunizing a healthy duck flock, preparing eggs, carrying out acidizing treatment, octoate treatment and refining, extracting and purifying treatment after separating egg yolks, preparing and freeze-drying so as to obtain the duplex egg yolk antibody freeze-drying powder for the duck virus hepatitis and the duck plague. According to the duplex egg yolk antibody freeze-drying powder for the duck virus hepatitis and the duck plague and the preparation method thereof, viruses sampled in regions with high morbidity are separated, the virus strain with wider coverage range is sieved, the vaccine is prepared, the cold/hot acidizing treatment of an egg yolk solution is also carried out, the antibody loss is reduced, and the obtained egg yolk antibody freeze-drying powder has high recovery rate and high purity, can dissolve and act quickly and has no clinical side effect.