Abstract: OBJECTIVE To observe the association of quantitative parameters of chest CT with inflammatory factorsneutrophils (NE) count, C-reactive protein (CRP), procalcitonin (PCT), lactate dehydrogenase (LDH), interleukin (IL)-2, IL-4, IL-6,IL-10, tumor necrosis factor-α(TNF-α), interferon-γ(INF--γ) through the chest CT imaging findings of the patients with COVID-19. METHODS A total of 288 patients with COVID-19 who were treated in The First Affiliated Hospital of Soochow University from Dec. 1, 2022 to Jun. 30, 2023 were retrospectively enrolled in the study. The chest CT images were divided into the hyperventilation area, well-ventilated area, ground-glass opacity (GGO) area and consolidation area. The volume and percentage of the areas were calculated. The association of CT parameters with inflammatory factors was observed. RESULTS Among the 288 COVID-19 patients who were enrolled in the study, there were 126 (43.75%) cases of moderate type, 104 (36.11%) cases of severe type, and 58 (20.14%) cases of critically severe cases. The volume of GGO of chest CT and volume and percentage of pulmonary consolidation showed upward trends with the aggravation of illness condition (P＜0.05); while the volume and percentage of well-ventilated lungs showed downward trends(P＜0.05). The volume of GGO of two lungs of the critically severe patients was 801.77(615.51,1127.74)ml, with the percentage 38.18(25.05,48.24)%; the volume of the consolidated lungs was 282.41(203.96,474.25)ml, with the percentage 13.56(6.36,20.51)%; the volume of well-ventilated lungs was 961.84(600.18,1478.57)ml, with the percentage 39.78(29.43,55.98)%. The volume and percentage of well-ventilated lungs were negatively correlated with the above inflammatory factors; the volume of GGO, volume and percentage of consolidation were positively correlated with the above inflammatory factors, especially highly correlated with CRP, PCT and LDH. CONCLUSIONS With the aggravation of illness condition, the volume and percentages of GGO and consolidation on chest CT show upward trends, the volume and percentages of the well-ventilated lungs show downward trends, and the severity of chest CT is closely associated with the adverse clinical outcomes. The quantitative parameters of chest CT can reflect the inflammatory state and facilitate the clinical assessment of severity of disease.