Background: A new virus broke out in Wuhan, Hubei, China, that was later named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The clinical characteristics of severe pneumonia caused by SARS-CoV-2 are still not clear. Objectives: The aim of this study was to explore the clinical characteristics and risk factors of severe pneumonia caused by the SARS-CoV-2 in Wuhan, China. Methods: The study included patients hospitalized at the Central Hospital of Wuhan who were diagnosed with COVID-19. Clinical features, chronic comorbidities, demographic data, laboratory examinations, and chest computed tomography (CT) scans were reviewed through electronic medical records. SPSS was used for data analysis to explore the clinical characteristics and risk factors of patients with severe pneumonia caused by SARS-CoV-2. Results: A total of 110 patients diagnosed with COVID-19 were included in the study, including 38 with severe pneumonia and 72 with nonsevere pneumonia. Statistical analysis showed that advanced age, increased D-Dimer, and decreased lymphocytes were characteristics of the patients with severe pneumonia. Moreover, in the early stage of the disease, chest CT scans of patients with severe pneumonia showed that the illness can progress rapidly. Conclusions: Advanced age, decreased lymphocytes, and D-Dimer elevation are important characteristics of patients with severe COVID-19. Clinicians should focus on these characteristics to identify high-risk patients at an early stage.