Objective To investigate the effect of Suhuang Zhike capsule combined with doxofylline on chronic persistent bronchial asthma, pulmonary function and exhaled nitric oxide（FeNO）．Methods Seventy patients with chronic persistent bronchial asthma from March 2020 to March 2022 were randomly divided into two groups, 35 cases in each group．The control group was only treated with doxofylline, and the study group was treated with Suhuang Zhike capsule additionally．After 3 months of treatment, the patients were evaluated by asthma control test（ACT）, the acute exacerbation of asthma was recorded, and the pulmonary function and exhaled FeNO were measured．Results There was no statistical significance in the ACT score of the two groups after one month of treatment（P>0.05）．The ACT scores of the study group after two months and three months of treatment were significantly higher than those of the control group（P<0.05）．The times of acute exacerbation of asthma and the use of emergency drugs in the study group were less than those in the control group（P<0.05）, but there was no significant difference in the number of emergency hospitalizations between the two groups（P>0.05）．Compared with the baseline value, there was no significant change in lung function indexes in the two groups after 3 months of treatment（P>0.05）．Compared with the baseline value, there was no significant change in FeNO in the two groups after 3 months of treatment（P<0.05）, while FeNO in the study group was lower than that in the control group（P<0.05）．Conclusions Suhuang Zhike capsule combined with doxofylline in the treatment of chronic persistent bronchial asthma can reduce FeNO and improve the level of asthma control．