OBJECTIVE： To provide reference for rational use of drugs and improving the therapeutic effect of bronchiolitis Children. METHODS： Medical records and medical orders of moderate and severe bronchiolitis children were collected from our hospital during Jan. 2014 to Dec. 2016. Retrospective investigation was conducted for the use of main therapeutic drugs. The rationality of drug use was evaluated. RESULTS： A total of 423 children with moderate-to-severe bronchiolitis were included， the cure rate was 92.91％ and recovery rate was 6.86％. The utilization rate of inhaled corticosteroid （Budesonide suspension for inhalation） was 98.11％， and that of systemic corticosteroids was 27.90％. The utilization rate of bronchodilator anticholinergic agents and β2-receptor agonists were 74.70％ and 58.87％. That of leukotriene modifiers （mainly montelukast） was 85.58％. The utilization rate of nucleoside antiviral drugs （mainly ribavirin） was 15.37％， and those of intramuscular injection and aerosolized inhalation of interferon were 36.64％ and 17.73％. There was no statistical significance in therapeutic efficacy between without systemic glucocorticoid group and systemic glucocorticoid group （P＞0.05）. There was irrational drug use in 101 cases （23.88％） during the treatment of severe bronchiolitis. Among the types of supernormal drug use， most were off-label drug use without justified reasons （75 case time， 17.73％）， followed by unsuitable drug selection which was the type of unsuitable drug use （11 case time， 2.60％）. The third type of irrational drug use was the type of non-standard drug use as unstated reason and resignatures of drug overdose （hormone shock therapy， 8 case time， 1.89％）. CONCLUSIONS： The overall use of major bronchiolitis therapy drugs in our hospital is still acceptable. However， there still is irrational drug use in some medical orders， manifested as off-label drug use without justified reasons， unsuitable drug selection， unstated reason of drug overdose， resignatures， etc. It is suggested to formulate bronchiolitis drug use regulation that meet the actual conditions of the hospital， strengthen business training and rational drug use education， enhance the awareness of pharmacist to rational drug use， play the professional role of pediatric clinical pharmacists， review medical orders to find out the problems of irrational drug use and communicate with physicians in time.