Abstract： Objective To explore clinical significances of plasma tissue-type plasminogen activator(t-PA) and type 1 plasminogen activator inhibitor ( PAI-1 ) in acute exacerbation of chronic obstructive pulmonary disease (AECOPD).Methods Two hundred and three patients hospitalized with AECOPD from 2007 to 2010 were chosen as the AECOPD group,while 142 normal persons receiving general health check-up during the same period were arranged for normal control group.Results The value of plasma t-PA in AECOPD patients was significantly lower than that in the normal control group [ (4.4 ± 4.1 ) μg/L vs (7.3 ± 1.4) μg/L,P ＜ 0.01 ] ; and the value of plasma PAI-1 in AECOPD patients was significantly higher than that in the normal control group[ (42 ± 14) μg/L vs ( 19 ±9) μg/L,P ＜ 0.01 ].Conclusions The blood of patients with AECOPD is in a hypercoagulation state,which can easily result in thrombosis of small pulmonary arteries and arterioles.The detection of plasma t-PA and PAI-1 has a certain clinical significance in discovering if there is a hypercoagulation state in AECOPD patients in the early stage.