Objective To evaluate the application of fractional exhaled nitric oxide (FeNO) in the reducing treatment of bronchial asthma.Methods From October 2015 to September 2016,60 asthmatic patients with FeNO＞25 ppb were randomized into FeNO group and control group with 30 cases in each group.Patients in both groups were treated with combined inhaled corticosteroids and long-acting beta 2 agonist (ICS/LABA) starting with low doses;the dosage was adjusted according to the symptom control alone in control group,while in FeNO group the dosage was adjusted according to the symptom control and FeNO level.After 1 year-follow up,the Asthma Control Test (ACT) scores,Asthma Life Questionnaire (mini AQLQ)scores,pulmonary function,FeNO levels,blood eosinophil counts,total IgE,hierarchical control level,cumulative corticosteroid use and cumulative months of leukotriene receptor antagonists (LTRA) use were compared before and after treatment within group,and between two groups.Stratified analysis was carried out in the patients complicated with allergic rhinitis.Results After treatment,ACT scores,mini AQLQ scores and FEV1/pred (％) were significantly higher than those before treatmentin both groups (t=10.755,10.189,8.632 and 13.311,8.102,12.456,respectively,all P＜0.05),while the FeNO,EOS and total IgE levels were significantly lower than those before treatment (t=8.005,3.313,3.924 and 8.967,3.885,3.270,respectively,all P＜0.05),and the numbers of patients with good control were significantly increased (Z=-5.035 and-4.976 respectively,P＜0.05).Compared with control group,FeNO level was lower,mini AQLQ scores of symptom scores and emotional scores were higher and the average numbers of asthma attacks per patient per year were less after treatment in FeNO group (t=2.912,4.214,4.589,U=2.154,all P＜0.05).However,there was no significant difference in cumulative corticosteroid use and cumulative months of LTRA use between two groups (U=564.000 t=1.921 and 0.165,respectively,P＞0.05).For patients complicated with allergic rhinitis,the numbers of acute asthma attack were increased and the cumulative dosage of systemic corticosteroid use was higher in control group than those in FeNO group (both P＜0.05).Conclusion The reducing treatment strategy based on FeNO level and symptom control is of clinical value for patients with bronchial asthma,especially for those complicated with allergic rhinitis.