Objective： To app ly modified Yupingfeng powder prescription to intervene rats with chronic obstructive pulmonary disease(COPD)，observe its effect on the bacterial colonization of streptococcus， Neisseria， staphylococcus，flavobacterium，Citrobacter and campylobacter in the airway of COPD rats，and discuss the probable functional mechanism of the prescription.Methods：Selected 50 male Wistar rats in SPF grade，and divided theminto the normal group，the model group， the low-dose modified Yupingfeng powder prescription group， the middle-dose modified Yupingfeng powder prescription group and the high-dose modified Yupingfeng powder prescription group，10 rats in each group.Except the normal group，the other groups were given the method of lipopolysaccharide and smoking to establish the model of COPD rats.The concentration of modified Yu ping feng powder prescription in the low-dose，midd le-dose and high-dose group was 4.644 g/(kg·d)，9.288 g/(kg·d)and 27.864 g/(kg·d)respectively.By adopting high-throughput sequencing，detected and analyzed the relative content of 6 types of bacteria including streptococcus，Neisseria，staphylococcus，flavo bacterium，Citrobacter and campylobacter in bronchoalveolar lavage fluid of rats in each group.By means of hematoxylin-eosin(HE)staining，observed the histopathologic changes of right lung tissue.Results：Comparing with the normal group，the relative content of streptococcus，Neisseria，staphylococcus，flavobacterium，Citrobacter and campylobacter in the airway of rats in the model group was all significantly increased，difference being significant(P ＜ 0.05).Comparing with the model group，the relative content of streptococcus，Neisseria，campylobacter，flavobacteriumand staphylococcus in the airway of rats in the low-dose modified Yupingfeng powder prescription group was all significantly decreased(P ＜ 0.05)；the relative content of staphylococcus，flavobacteriumand Citrobacter in the airway of rats in the middle-dose modified Yupingfeng powder prescription group was all significantly decreased(P ＜ 0.05)；but there was no significant difference being found in the relative content of 6 types of bacteria in the airway of rats in the high-dose modified Yupingfeng powder prescription group(P＞0.05).Conclusion：Modified Yupingfeng powder prescription in lowand middle dose can decrease the partialbacterial colonization in the airway of COPD rats，but the high-dose one has no significant clinicaleffect in reduction.