Abstract: Objective To explore the value of multislice spiral CT (MSCT) imaging in evaluating small airway function in patients with chronic persistent asthma. Methods A total of 102 patients who were diagnosed with chronic persistent asthma at Department of Respiration and Department of Acupuncture Rehabilitation in Jiangsu Province Hospital of Chinese Medicine from October 2021 to October 2023 were included. All patients underwent chest MSCT imaging, pulmonary function tests (PFT), and fractional exhaled nitric oxide (FENO) measurements. The correlation between the examination indicators was analyzed, and the differences between the small airway dysfunction (SAD) group and the non-SAD group were compared. The diagnostic efficiency of MSCT small airway imaging for SAD was evaluated. Results The small airway wall thickness (WT), the ratio of wall thickness to cross-sectional diameter (TDR), and the ratio of wall area to total cross-sectional area (WA%) showed no correlation with patient gender, age, body mass index (BMI), disease duration, or FENO (P>0.05). TDR and WA% were significantly negatively correlated with pulmonary function indicators such as the percentage of the measured value to the predicted value for the following pulmonary function parameters: forced expiratory volume in 1 second (FEV1%), forced vital capacity (FVC%), FEV1/FVC ratio (1-second ratio), peak expiratory flow (PEF%), PEF at 25% of forced vital capacity (PEF25%), PEF at 50% of forced vital capacity (PEF50%), PEF at 75% of forced vital capacity (PEF75%) and maximal mid-expiratory flow (MMEF%) (P<0.001). WT was negatively correlated with PEF25%, PEF50%, PEF75%, and MMEF% (P<0.05), but showed no significant correlation with FVC%, FEV1%, FEV1/FVC, or PEF% (P>0.05). The presence of bronchiolitis at end-inspiration was weakly positively correlated with FeNO (P<0.05). Compared with the non-SAD group, the SAD group showed significantly increased age, BMI, and disease duration (P<0.05), with markedly reduced pulmonary ventilation function indicators (P<0.001). The SAD group presented significantly higher than MSCT small airway qualitative indicators (end-inspiratory bronchiolitis and end-expiratory air trapping) and quantitative indicators (WT, TDR and WA%) than the non-SAD group (P<0.05). No significant differences were found between the two groups in terms of gender and FeNO values (P>0.05). The ROC curves for small airway WT, TDR, WA%, end-inspiratory bronchiolitis, and end-expiratory air trapping showed areas under the curve of 0.676, 0.738, 0.748, 0.683, and 0.640, respectively (P<0.05), all with statistical significance. Conclusions SCT small airway imaging can accurately assess small airway function in asthma patients.