Background This study aimed to find the correlation between severe computed tomography (CT) lung scores and nasopharyngeal viral load (Ct value) in the severity of COVID‐19 disease progression. Method In this study, 37 patients diagnosed with COVID‐19 were categorized into severely ill and not severely ill samples. Their Ct values, epidemiological data, lung CT, and laboratory test results were collected three times, respectively, on the first day of their hospital admission, 3–5 days thereafter, and prior to hospital discharge. Among the 37 patients, 8 progressed from not severely ill to severely ill; we also paid attention and observed changes in clinical parameters of COVID‐19 patients who entered our city from other cities (imported cases) and the infected local residents who contacted these imported patients (non‐imported cases). Results Among the 37 patients, the Ct values and lung severity scores (LSSs) were similar in imported and non‐imported cases (F = 0.59 and 2.56; p = 0.45 and 0.12, respectively) but the proportion of severely ill imported patients was significantly higher compared with non‐imported patients (F = 7.77; p = 0.01). Additionally, 21.6% of patients' illness worsened; lymphocyte counts and Ct values were significantly lowered, and C‐reactive protein and LSS significantly increased during COVID‐19 disease progression. Furthermore, LSS negatively correlated with lymphocyte and mononuclear cell counts, as well as Ct values (Pearson's rank = −0.763, −0.824, and −0.588; p = 0.028, 0.012, and 0.003, respectively). Conclusion In the severity of COVID‐19 disease progression, nasopharyngeal viral load and lung CT severity were closely related, and LSS negatively correlated with lymphocyte and mononuclear cell counts, as well as Ct values.