Coronavirus Disease 2019 (COVID-19) is a pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak began in Wuhan, China, and spread rapidly, with many cases confirmed in multiple countries. Usually, after viral pneumonia were clinical cured, the pulmonary lesions of majority patients will gradually be absorbed to complete dissipation, very few severe patients may retain pulmonary interstitial inflammation and fibrosis. In this case, we described one unique COVID-19 patient, the symptoms were: dry cough, fatigue, poor appetite and subjective fever, moreover, the patient was a non-smoker, had no pulmonary bullous, no history of tuberculosis, and also no hypertension or diabetes. The patient received antiviral therapy, antibacterial therapy, recombinant human interferon-α2a, vitamin C and oxygen inhalation. After two weeks of treatment and observation, the patient was clinical cured and discharged. However, two days later, the patient had a sudden chest stuffiness, CT images indicted: his lung didn't heal like others, but developed a large pulmonary cavity in the lower lobe of right lung. In hospital, the patient showed no symptoms of infection for another 14 days, and the pulmonary cavity remain unchanged. This case suggested: it is important to follow convalescent COVID-19 patients, especially their lung CT images, to make sure a fully recovery.