Abstract: Objective To explore the changes of urokinase plasminogen activator(uPA) system, and to analyze and evaluate the relationship between uPA system and prognosis. Methods Coagulation indexes of lung cancer patients before and after chemotherapy and the healthy in control group were recorded. Peripheral blood concentration of uPA, tissue-type plasminogen activator(tPA) and plasminogen activator inhibitor-1(PAI-1) were measured by enzyme-linked immunosorbent assay(ELISA). Results All blood coagulation-fibrinolytic indexes of lung cancer patients in both before chemotherapy (Group A1 ) and after two cycles of chemotherapy ( Group A2) were significantly higher than that in normal control group (Group B)(P<0.05). Comparing Group A1 with Group A2, the coagulation indexes of platelet count(PC), prothrombin time(PT), activated partial thromboplastin time(APTT) had no significant difference(P>0.05). However, blood concentrations of D-dimer, tPA, uPA, PAI-1 in Group A2 were significantly higher than those in Group A1(P<0.05). In Group A2, the hierarchical analysis showed that both of plasma concentrations of uPA and D-dimer in progressive treatment cases were higher than those in clinical benefit cases (all P<0.05). uPA and D-dimer, tPA, PAI-1 which were changed significantly before and after chemotherapy were positively linear correlated, and the correlation coefficients were 0.472, 0.624, 0.575(all P<0.01). Meanwhile tPA and PAI-1 also were positively linear correlated(r= 0.61, P<0.001). Conclusion Lung cancer patients are suffered with dysfunction of coagulation-fibrinolytic system, and chemotherapy may exacerbate this anomaly, especially more sensitive to changes in fibrinolytic parameters. Low plasma concentrations of uPA and D-dimer in lung cancer patients contribute to good curative effect of chemotherapy, with positive correlation. Therefore, uPA D-dimer might be prompt indexes of the prognosis of lung cancer patients.