The invention relates to a Chinese medicament oral liquid for preventing and treating duck virus hepatitis and a preparation method thereof. The Chinese medicament oral liquid is characterized by being prepared from the following medicaments in portion by weight: 1 to 5 portions of indigowoad root, 1 to 5 portions of indigowoad leaf, 1 to 3 portions of Sinkiang arnebia root, 1 to 4 portions of kudzuvine root, 1 to 5 portions of virgate wormwood herb, 1 to 2 portions of rhizoma coptidis, and 1 to 5 portions of baical skullcap root. The preparation method comprises the following steps: (1) weighing 1 to 5 portions of the indigowoad root, 1 to 5 portions of the indigowoad leaf, 1 to 3 portions of the Sinkiang arnebia root, 1 to 4 portions of the kudzuvine root, 1 to 5 portions of the virgatewormwood herb, 1 to 2 portions of the rhizoma coptidis, and 1 to 5 portions of the baical skullcap root as raw material in portion by weight; and (2) adding water in an amount which is 4 times of thatof the medicinal materials, decocting the mixture twice with 1.5 hours each time, combining the decoctions, filtering the mixture, filtering the mixture, standing the filtrate for 12 hours, and taking the supernatant fluid and concentrating the supernatant fluid until the relative density is between 1.20 and 1.25; and adding ethanol into the supernatant fluid until the alcohol content is 60 percent, standing the mixture, filtering the mixture to reclaim the ethanol, adding water into the mixture until the relative density is between 1.10 and 1.15, filtering and encapsulating the mixture, andcirculating steam at a temperature of 100 DEG C for 30 minutes. The Chinese medicament oral liquid has the advantages of quick response, absolute curative effect, no drug residue, and no toxic side effect.