Objective: To retrospectively investigate the clinical manifestations and imaging features of heavy novel coronavirus pneumonia (NCP). Materials and methods: Fifty-two patients with positive chest computed tomography (CT) manifestations and a confirmed diagnosis of COVID-19 in the Infection Unit from November 2022 to January 2023 were included in our study. All patients underwent chest thin-section CT examination and had more complete clinical data from 1 to 14 days after onset. Patients were divided into two groups based on the time interval between onset and CT examination (<7 and ≥7 days), and the differences in CT performance characteristics between the two groups were compared. Results: Among the 52 patients with severe COVID-19, the age range was approximately 53 to 97 years, with a median age of 80 years in 4 men and 18 women. Thirty-three patients (63.5%) with underlying diseases were combined, including 2 (3.8%) with pulmonary disease, 6 (11.5%) with diabetes mellitus, 18 (34.6%) with hypertension, 16 (30.8%) with coronary heart disease, and 7 (13.5%) with cerebrovascular disease. The main symptoms of patients included fever in 44 (84.6%), cough in 43 (82.7%), myalgia in 2 (3.8%), sore throat in 19 (36.5%), chest tightness in 9 (17.3%), diarrhea in 2 (3.8%), and poor appetite in 3 (5.8%). The differences in lesion involvement and lesion size were statistically significant between patients grouped at the time interval between onset and CT examination. Conclusions: Severe COVID-19 is more common in older adult males, mostly combined with underlying disease. CT features include more airway involvement in the short term, and bloodway involvement is more common in those with longer onset.