Objective:To investigate the clinical data of asymptomatic patients with 2019 novel Coronavirus (2019-nCoV) infection in Shijiazhuang and provide scientific evidence for prevention and treatment of Coronavirus Disease 2019(COVID-19).Methods:Retrospective study was conducted to analyze the clinical features and laboratory data of 9 asymptomatic 2019-nCoV infected patients, admitted to the Fifth Hospital of Shijiazhuang from January 21, 2020 to February 21, 2020.Results:Asymptomatic infection was found in all age groups, including 5 males and 4 females. On the first day of admission, the detection result of leukocytes, lymphocytes and neutrophils in asymptomatic patients were at normal levels. On the third day after admission, the results increased and continued to stabilize on the twelfth day. The levels of alanine aminotransferase and lactate dehydrogenase were at normal levels during hospitalization, without transient increase or decrease. The level of C-reactive protein reached the highest level on the third day after admission, but it was always in the normal range. D-dimer level was relatively stable during hospitalization. The absolute value of T cell subsets showed that the levels of CD 3+ , CD 4+ , CD 8+ T cells in asymptomatic infection patients were higher than those determined before admission. The average duration of pharyngeal nucleic acid positive detection in asymptomatic patients was 11.88 days. The average cycle threshold of ORF1ab gene and N gene was 36.94 and 35.43 respectively. Conclusions:The inflammatory reaction in patients with asymptomatic 2019-nCoV infection was mild, and the immune function was relatively good.