Objective: Comparison the test result of exhaled nitric oxide (FeNO) level and pulmonary function for the patients with bronchial asthma. We will find the fast、efficient method for early diagnosis of bronchial asthma. Methods:I determined 90 cases of suspected patients of bronchial asthma with Foundation pulmonary function、Exhaled nitric oxide measurement and Brinchial provocation test. Results: The results of 90 cases Foundation pulmonary function are normal, the cases of FeNO increased are 86 among them, the positive rate is 95%;the Positives of brinchial provocation test are 75 among them, the positive rate is 83%. FeNO and bronchial provocation test showed a moderate positive correlation. The timeliness and safety of FeNO determination is better than that of bronchial provocation test, and the difference was statistically significant (P<0.05). Conclusion: A correlation between FeNO and airway reactivity. IF we compared exhaled nitric oxide and bronchial provocation test for early diagnosis of bronchial asthma,FeNO is simple, safe, fast, and it is easy for patients to accept the advantages. But FeNO is affected by many factors, it’s reference value is also no uniform standards, the further research is needed. For non allergic asthma patients, although FeNO determination is normal, we cannot exclude asthma, determination of BHR still need for further definite diagnosis.目的：比较支气管哮喘患者呼出气一氧化氮 (FeNO) 水平与肺功能检测结果。探寻支气管哮喘早期诊断的快速、高效方法。方法：对90例疑似支气管哮喘患者进行基础肺功能测定、呼出气一氧化氮测定及支气管激发试验。结果：90例患者基础肺功能正常，其中FeNO增高者86例，阳性率95%；其中支气管激发试验阳性者75例，阳性率83%。FeNO与支气管激发试验呈中度正相关。FeNO测定方法的用时、安全性优于支气管激发试验，且两者差别（P＜0.05)具有统计学意义。结论: FeNO与气道反应性具有相关性。呼出气一氧化氮检测在支气管哮喘早期诊断中较支气管激发试验具有简单、安全、快捷，病人易于接受的优点。但FeNO受多种因素的影响，其参考值尚没有统一认可的标准，有待进一步的研究。对于非过敏性的哮喘病人，虽然FeNO测定正常，但并不能排除哮喘，还需要BHR测定进一步确诊
