Objective To investigate the changes of small airway function，airway resistance and responsiveness of extrathoracic airway in chronic cough patients before and after bronchial provocation test (BPT)．Methods 68 chronic cough patients were requested to conduct lung function test and BPT．The airw ay resistance were measured via forced oscillationary technology before and after BPT．Results BPT revealed airway hyperresponsiveness in 52％subjects．MEF50 and R0 before BPT were significantly different between the patients with or without airway hyperresponsiveness．Post BPT changes in MEF50(MEF50％) were correlated positively to the changes in FEV1(FEVl％)，and negatively to the changes in R0[Ro-d]． Extrathoracic airway hyperresponsivenes(EAHR)was f0und in13 patients，in which 6 patients were not revealed by routine BPT．Conclusion There is small airway function abnormalities in chronic cough patients．Extrathoracic airway responsiveness test is a valuable supplementary index to routine BPT．