Objective To study the transmission risk of asymptomatic patient in a family-clustered outbreak of new coronavirus pneumonia, analyze the hospitalization,and provide a basis for prevention strategies and treatment plan. Methods We collected the information about residence history and exposure risks by onsite epidemiological investigation, and collected clinical treatment-related data, used statistical software for mapping and analysis. Results The incubation period of the indicated case was 15 days, and the incubation period of the remaining four family members were 1-15 days. The indicated case as an asymptomatic patient had infectious succession within 4-6 days after infection,and four family members were infected one after another. The indicated case carried the virus for more than 8 days, and the remaining 4 patients ranged from 2 to 31 days. The duration of symptoms was 5-20 days of all 5 patients, and the number of CT examinations during hospitalization was 4-10 times. The pulmonary inflammation was improved on the third day of hospitalization at best. In the early stage of the disease, only one patient had leukopenia and lymphopenia decreased. The interval between onset and hospitalization was 1-10 days for five family members, with an average hospitalization time of 23.4 days. Conclusion The asymptomatic infected patient of COVID-19 plays a key role in the family convergence epidemic transmission. The symptoms are inapparent, so it is difficult to find in time. It will cause the risk of infection and increase the difficulty of COVID-19 prevention and control.