Abstract: Objective: Objective: To explore and analyze the clinical features and chest thin-slice non-enhanced computed tomography (CT) imaging features of patients with coronavirus disease 2019 (COVID-19) at initial diagnosis in a fever clinic. Methods: A retrospective analysis was performed on 140 patients with COVID-19 at initial diagnosis in a fever clinic, including 101 and 39 cases in the moderate and severe and critical groups , respective-ly. Baseline, clinical characteristics, complete blood count + C-reactive protein (CBC+CRP), and chest thin-slice non-enhanced CT imaging characteristics of the patients were analyzed. Results: (1) The comparison between the moderate and severe and criti-cal groups showed that there were statistically significant differences in age (66.05±14.38 vs. 77.90±13.12,), course of initial diagnosis (5.40±3.81 vs. 3.97±3.12), SPO₂ (97.88±1.73 vs. 92.92±4.01)_, and Tmax (38.32±0.66 vs. 38.68±0.63).(2) CT features between the two groups showed statistically significant differences in semi-quantitative volume (18.85±13.51 vs. 34.41±19.34). (3) The comparison between the moderate and severe and critical groups showed that there were statistically significant differ-ences in CRP (29.42±26.93 vs. 80.67±48.01), LYM (1.64±0.68 vs. 0.95±0.64), and NLR (3.48±2.46 vs. 9.36±10.42). (4) Six indicators, namely age, the course of initial diagnosis, SPO2, semi-quantitative volume, CRP, and LYM, were screened for multivariate logistic regression analysis. The result show that age (OR=1.090, 95%CI 1.006 ~ 1.181), semi-quantitative (OR=1.086, 95%CI 1.086 ~ 1.019), and SPO₂ (OR=0.261, 95%CI 0.089 ~ 0.762), are related to the occurrence of severe and critical COVID-19 infection, and the difference is statistically significant; CRP (OR=1.054, 95%CI 1.023 ~ 1.087) and LYM (OR=0.039, 95%CI 0.04 ~ 0.391) are related to the occurrence of severe and critical COVID-19 infection, and the difference is significant statistically significant. Conclusion: Age, lower SPO₂ and LYM, a shorter course; a higher Tmax, semi-quantitative volume, CRP, and NLR are associ-ated with severe and critical cases and required early identification.