Acute asthma attack continues to be a major cause for children admitted to the emergency room. Nebulized beta 2-adrenergic agonists are still the first-line drugs for a rapid bronchodilation effect and an easily administered drug during acute asthma attack. The bronchodilator-induced hypokalemia is thought significant in adult group, but is often ignored in children group. In this study, we conducted a randomized study to compare the laboratory and clinical effects between nebulized salbutamol and terbutaline. We found that both salbutamol and terbutaline nebulization induced a significant hypokalemia (p < 0.05). Terbutaline nebulization also significantly improved the peak expiratory flow rate (PEFR) and respiratory rate (RR), but not venous partial pressure of oxygen (PvO2), venous carbon dioxide tension (PvCO2) and O2 saturation in venous blood (SvO2). In contrast, salbutamol improved not only PEFR and RR, but also PvO2, PvCO2, and SvO2 30 minutes of administration. In conclusion, the nebulized salbutamol, although induced a hypokalemic effect which is similar to terbutaline group, has a better effect on improving O2 saturation than nebulized terbutaline with the same dose 30 minutes after administered for children with acute asthma attack.