Objective To examine the levels of fractional exhaled nitric oxide in bronchial asthma and the cor-relation between fractional exhaled nitric oxide and pulmonary function tests as well as the value of pulmonary function tests in curing the children with bronchial asthma. Methods Seventy - two asthmatic children came from Guiyang Ma-ternal and Child Health Hospital were studied. They were divided into 2 groups:mild - to - moderate asthma group(36 cases)and serious asthma group(36 cases). Fractional exhaled nitric oxide level and the lung function were measured and the correlation analysis was analyzed by SPSS 13. 0 software. Results The fractional exhaled nitric oxide concen-tration of the serious asthma group was significantly higher than that of the mild - to - moderate asthma group[(47 ± 26)ppb vs(29 ± 15)ppb,t = 3. 543,P ﹤ 0. 01],1 - second rate,maximum mid - expiratory flow(MMEF),and peak expiratory flow(PEF)in mild - to - moderate asthma group were significantly higher than those in serious asthma group[(99. 74 ± 9. 81)% vs(87. 17 ± 13. 30)% ,(87. 12 ± 35. 61)% vs(68. 90 ± 30. 88)% ,(99. 97 ± 10. 83)% vs (94. 31 ± 17. 69)% ](P ﹤ 0. 01,0. 05,0. 05). No correlations were found between fractional exhaled nitric oxide level and the lung function parameters,including forced expiratory volume in 1s(FEV1),1 - second rate,MMEF and PEF in the mild - to - moderate asthma group(r = 0. 073,0. 087,0. 242,0. 326,all P ﹥ 0. 05). However the level of fractional exhaled nitric oxide was negatively correlated with the lung function parameters,including FEV1,FEV1 / FVC,MMEF and PEF in serious asthma group(r = - 0. 354,- 0. 573,- 0. 478,- 0. 471,P ﹤ 0. 05,0. 001,0. 005,0. 005),respec-tively. Conclusions Monitoring of fractional exhaled nitric oxide and the lung function parameters can effectively indi-cate the state of illness of asthmatic child,which plays a key role in the treatment.