The incubation period of natural infection of African swine fever is 5-9 days, and the clinical experimental infection is 2-5 days. At the onset, the body temperature rose to 465,438 0℃ for about four days. Until 48 hours before death, the body temperature began to drop. At the same time, the clinical symptoms only appear after the body temperature drops, so it is different from the symptoms of African swine fever when the body temperature rises. In the first three to four days of fever, the pig's appetite is extremely fragile and the pig lies in the corner. It is characterized by extreme fatigue, especially in the hind limbs, rapid pulse, cough, rapid breathing by about one third, obvious dyspnea, serous or mucinous purulent conjunctivitis, and some strains can cause bloody diarrhea, vomiting, and blood changes similar to classical swine fever. Three to five cases show that the number of white blood cells is reduced by 50% and the number of lymphocytes is also reduced. Leukemia occurs when the body temperature rises, and white blood cells are on the fourth day.