Objective To study the curative effect of Montelukast in bronchiolitis and to evaluate the efficiency of montelukast in decreasing the incidence of asthma following brochiolitis.Methods 90 cases bronchiolitis were categorized in two groups,therapy group 45 cases and control group 45 cases,conventional Medical treatment were given in two groups,Montelukast was appendant in therapy group,4mg,qn,4 weeks.The time of follow up was over 1 year.Results The cure rate of therapy group was significant higher than control group(P0.01),the difference had statistical value.Incidence of asthma following brochiolitis with montelukast was less than without montelukast.Conclusion Montelukast can conspicuous increase the therapy effects of bronchiolitis,Montelukast is an effective way to decrease the incidence of asthma following brochiolitis.Using Montelukast is a good way to precaut the asthma following brochiolitis,and it is not adverse reactions.