Preparation method of beer roast duck. First, choose the duck with white stripes. 2. Prepare spices, including: clove, nutmeg, fennel, star anise, fragrant fruit, tsaoko, cinnamon, cumin, fragrant leaves, row grass, etc. Add onion, ginger and garlic. Third, add pork bones, chicken bones and old duck bones to cook spices for three hours. Fourth, add edible seasonings, including salt, monosodium glutamate, honey and beer. 5. Marinate the washed duck in salt water for 8- 12 hours, depending on the climatic conditions. 6. Take out the salted duck with white stripes and drain. Seven, baking. The temperature is gradually reduced from 230 to 200, and the roast duck is roasted for 2 to 3 hours. The time depends on the climatic conditions and the heat preservation performance of the oven, and the duck can be roasted until golden brown.