The efficacy of β 2 agonist in the treatment of bronchiolitis has been questioned. This study aims to explore the changes of pulmonary function in infants with acute bronchiolitis before and after treatment with nebulized salbutamol. Methods Thirty infants with bronchiolitis were randomly assigned into a Treatment group (nebulized salbutamol, 0.15 mg/kg in 2 ml normal saline; n=16) and a Control group (2 ml normal saline; n=14). Tidal breathing flow volume (TBFV) loops and static respiratory system compliance (Crs) and resistance (Rrs) were measured before nebulization and immediately after nebulizer treatment, and 15 minutes and 30 minutes after treatment. Results A significant improvement in the percentage of tidal volume to peak tidal expiratory flow (%V/PF) was found in the treatment group 30 minutes after nebulization (0.184±0.05 vs 0.13±0.04; P< 0.05 ). Terminal flows/peak expiratory flow (25/PF) and peak tidal expiratory flow (PTEF) of the Treatment group also tended to improve, but there were no differences. There were also significant differences in 25/PF and inspiratory time (Ti) immediately after nebulization between the two groups. Conclusions Salbutamol treatment appears to improve peripheral airway resistance and ventilation in children with acute bronchiolitis.