Based on the characteristics of the clinical symptoms of coronavirus disease 2019（COVID-19）

the concept of the prodromal period of COVID-19 is proposed

and it is believed that the prodromal period of COVID-19 refers to the beginning of the appearance of inapparent respiratory symptoms to the clinical symptoms reaching the standard in the early stage of diagnosis of COVID-19. According to the understanding of COVID-19 and the principles of prevention and treatment in traditional Chinese medicine（TCM）

combined with the climate characteristics

residents′ physical characteristics and eating habits in Beijing etc.

we analyzed the syndrome elements and pathogenesis of the prodromal period of COVID-19 in Beijing. It is believed that the common symptoms of the prodromal period include dry throat

sore throat

dry mouth

dry nose

dry cough

lack of phlegm

bitter mouth

peculiar smell in the mouth

little appetite

abdominal distension. The nature of the disease is dry

hot

damp

and the disease location is in the lungs

stomach and intestines. The pathogenesis is the external invasion of epidemic toxin

pathogen offenses nasopharynx or pathogen offenses stomach and intestine. Yinhua Qingfei Drink is developed on the basis of Yinqiao Powder（银翘散） and Shashen Maidong Decoction（沙参麦冬汤） in Wenbing Tiaobian（《温病条辨》）

and its preventive effect on patients with COVID-19 in Beijing area was discussed.