Aim To observe the changes of fibrinolytic activityin plasma of patients with atherosclerotic diseases and the relation between the fibrinolytic activity and the serum lipids.Methods 31 patients with atherosclerotic diseases were compared with 30 healthy subjects.Results The type 1 plasminogen activator inhibitor (PAI-1) activity and the tissue type plasminogen activator(tPA) antigen in plasma were higher in the atherosclerotic than in the control group (12. 50±5. 06vs 6. 93±3.82 kAU/L,P=0. 0031: and8. 94±3.53vs 5.36±2.33 μg/L,P=0. 0001) , respectively In personal correction analysis , plasma PAI-1 activity correlated positively with serum total cholesterol(TC),triglyceride (TG) and low density lipoprotein cholesterol (LDLC)(r=0. 270～0. 526.P=0. 0001～0.0356).The plasma tPA antigen correlated positively with serum TG(r=0.32.P=0.0101).Conclusions The hypofibrinolysis is due to the plasma PAI-1 level elevating , but not to the tPA less producing.The higher serum concentration of TC and TG could stimulate the PAI-1 synthesis and secretion by the endothelium , which impaires fibrinolyticactivity in plasma.