〔Abstract〕 Objective To study the effect and mechanism of astragalus extract on airway resistance and lung function in mice with bronchial asthma. Methods A BALB/c mouse model of bronchial asthma was established by the ovalbumin method, and divided into a low-dose astragalus extract treatment group (L-ASE group, administered with 5 mg·mL^-1 astragalus extract) and a high-dose astragalus extract treatment group (H-ASE group, administered with 5 mg·mL^-1 astragalus extract). The successful bronchial asthma mouse model was selected as the model group, and normal mice were selected as the control group. The 2-min cough times, specific airway resistance (sRaw), airway resistance (RI), tidal volume (TV), minute ventilation (MV), static lung compliance (Cst), the levels of serum tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6 among the four groups of mice were checked and compared. Results The cough times in 2 minutes, the levels of sRaw at concentrations of 0 mg·mL-1, 5 mg·mL-1, 10 mg·mL^-1, 15 mg·mL^-1 of acetylcholine, RI, Cst, the levels of serum TNF-α, IL-1β, IL-6 in the model group were significantly higher than those in the control group, the levels of TV and MV were significantly lower than those in the control group, and the differences were statistically significant (P < 0.05). The cough times in 2 minutes, the levels of sRaw at concentrations of 0 mg·mL-1, 5 mg·mL^-1, 10 mg·mL^-1, 15 mg·mL^-1 of acetylcholine, RI, Cst, the levels of serum TNF-α, IL-1β, IL-6 in L-ASE group and H-ASE group were significantly lower than those in the model group, the levels of TV and MV were significantly higher than those in the model group, and the differences were statistically significant (P < 0.05). The cough times in 2 minutes, the levels of sRaw at concentrations of 0 mg·mL^-1, 5 mg·mL^-1, 10 mg·mL^-1, 15 mg·mL^-1 of acetylcholine, RI, Cst, the levels of serum TNF-α, IL-1β, IL-6 in H–ASE group were significantly lower than those in the L-ASE group, the levels of TV and MV were significantly higher than those in the L-ASE group, and the differences were statistically significant (P < 0.05). Conclusion Astragalus extract can significantly improve the airway resistance and lung function of bronchial asthma mice, and the mechanism may be related to the down-regulation of inflammatory response in bronchial mice.