(1) Prepare 38kg of soybeans, 28.5kg of flour, 0/2.5kg of salt, 5g of shredded tangerine peel, 62.5l of watermelon juice, 0.75kg of ginger and 5g of fennel. (2) Soaking beans: wash soybeans with clear water, remove impurities from the floating soil, take them out and put them in a jar, and soak them in clear water for 3-4 hours. (3) Steamed and soaked soybeans are boiled at normal pressure for 3-4 hours until they are kneaded into cakes with fingers without hard hearts. (4) The traditional method of steaming beans to make koji makes natural Aspergillus flavus grow and reproduce naturally. Mix steamed soybeans and flour evenly, spread them on a reed mat about 3 cm thick, keep the room temperature at 28 ~ 30℃ and the koji temperature at 35 ~ 37℃. 1 days later, it became a block for the first time. After that, I turned to the song for the second time about 6 hours. After three days of heat preservation culture, when all the soy sauce koji materials are tender yellow, the soy sauce koji becomes a koji. After the song was played, it was tanned in the scorching sun. (5) Fermented grains: uniformly mixing watermelon juice with salt, Jiang Mo, shredded dried tangerine peel and fennel, then mixing dried beancurd, putting in a jar, soaking and differentiating in the sun, and sealing the jar for fermentation for 40-50 days when the salt is completely dissolved and the thin consistency of fermented beancurd is suitable (15 days or more). (6) The characteristic color of the finished product is fresh and tender, the bean paste is mixed, the taste is refreshing, the umami flavor is rich and sweet, the smell is fragrant and soft, and it has the effect of invigorating the stomach and helping meals. When eating, it can be fried with appropriate amount of sesame oil or Chili oil or processed into spicy bean paste.