Objective To explore airway remodeling and air trapping in asthmatic patients with low dose CT scanning and quantitative analysis. Methods 52 stable asthmatic patients in which 29 were severe and 23 were slight,and 20 healthy control cases were underwent low dose dual phase CT scanning. The LA/BSA, WA/BSA, TA/BSA, WA%and Pi10WA were analyzed as airway remolding indexes. The MLD of expiratory, VI-850 (%) of expiratory, MLD E/I, VI-850E-I (%) and VI-850/-950E-I (%) were analyzed as air-trapping indexes. One-Way ANOVA or H Kruskal-Wallis was used to analyze the above indicators. Results Airway remodeling indexes and LA/BSA were (9.6 ± 2.6), (11.0 ± 3.4) and (12.6 ± 3.0)mm2/m2 in severe asthmatics group, non-severe asthmatics group and healthy control group respectively, and there was significant difference between the three groups (F=5.60, P=0.006). WA%of each group was (65.1 ± 2.5)%, (63.3 ± 4.4)%and (62.0 ± 3.0)%, and there was significant difference between the three groups (F=5.53,P=0.006). The Pi10WA was (18.4±2.6), (17.7±3.1) and (16.4±1.4) mm2 respectively with significant difference between the three groups (F=3.59 ,P=0.033). Air-trapping indexes, MLD of expiratory of each group was-(771 ± 59),-(724 ± 43) and-(676 ± 60) HU respectively with significant difference (F=5.60, P=0.006). VI-850(%) of expiratory of each group was 30.79(30.45)%, 13.53(12.09)%and 2.85(6.87)%respectively with significant difference (H=17.20,P<0.001). Conclusions Low dose of CT scan and quantitative analysis can provide an objective and quantitative information for patients with airway disease of asthma, and both WA% and Pi10WA were objective indexes. The severe asthmatic patients were associated with obvious airway remodeling and air trapping compared with non-severe asthmatic patients.