Abstract: The coronavirus disease 2019 (COVID-19) is a new infectious disease, firstly appeared in Wuhan city and has rapidly spread to 114 countries outside China, which is receiving worldwide attention. As two important means of examination, computed tomography (CT) and real-time reverse transcription polymerase chain reaction (RT-PCR) have always been controversial in the clinical diagnosis of COVID-19 pneumonia. Here, we report a family cluster case of a father and a son diagnosed as COVID-19 at our hospital, and described the clinical manifestations, laboratory results, CT changes, diagnosis and treatment strategy of these two patients. Focus on the value of these two methods in the diagnosis and treatment of diseases, as well as their respective deficiencies. For patient 1 (father), the efficacy of RT-PCR is not satisfactory either in terms of diagnosis or follow-up, which may cause misdiagnosis and delay treatment. For patient 2 (son), the clinical symptoms were not obvious, but CT imaging clearly displayed dynamic changes of the lung lesions. Meanwhile, the two patients respectively underwent five chest CT examinations during their hospitalization and discharge follow-up, showing the potential harm of radiation. Therefore, in clinical work, doctors should make full use of the advantages of CT and RT-PCR, and take other measures to make up for their disadvantages.