Symptoms appear as soon as 1 day and as late as 24 days after infection with the new coronavirus, usually 1-14 days. Most patients in 3-7 days will appear in fever, dry cough, malaise, mainly clinical manifestations, a few patients with nasal congestion, runny nose, sore throat, myalgia and diarrhea, etc. Severe patients tend to develop respiratory distress and hypoxemia 1 week after the onset of the disease, and in severe cases, the rapid progression of acute respiratory distress syndrome and so on. Infection is not absolutely will appear symptoms, the body infected with the new coronavirus is not in passive defeat, will go with the virus to fight. Symptoms will appear when the virus is large in number, virulent, and the body’s resistance is weak. When the body resistance is strong and the number of viruses is not large and virulence is not strong, symptoms can not appear, at this time is the new coronavirus infection appeared to be a setback, the body towards recovery.