To investigate the clinical outcome of patients with moderate type of corona virus disease 2019 (COVID-19) after discharge by retesting viral nucleic acid.Seven patients with moderate COVID-19 met the discharge criteria enacted by National Health Commission were quarantine in hospital for 7 days, then continuously quarantined at home for 4 weeks after discharged. During the three weeks of quarantined period, the symptoms and signs were documented; and sputum or nasal swab and feces samples were collected to test SARS-COV-2 nucleic acid by RT-PCR method.There were no symptoms and signs during the quarantine period in all 7 patients. However, respiratory swabs from 3 patients were confirmed positive of SARS-COV-2 nucleic acid at 5 to 7 days after they met the discharge criteria.The study indicates that there is a relatively high incidence of positive viral nucleic acid in patients met the discharge criteria, and it is suggested that patients met the current discharge criteria should be quarantined in hospital for another 7 days and the follow-up viral testing is necessary.