Aim To study the change of EPC and expression of its tPA and PAI in patients with coronary heart disease. Methods EPC isolated from peripheral blood of patients with coronary heart diseases(n57) and control (n30) were cultured and tPA and PAI in the supernatant were determined by ELISA and Substrate chemiluminescence.The expression of tPA mRNA and PAI mRNA were detected by RT-PCR. Results The number of EPC was significantly reduced in patients with CAD compared with control subjects. The cell colony forming was also decreased in patients with CAD. The concentration and activity of EPC patients with CAD were lower than EPC of control group. The tPA mRNA expression, the concentration and activity of EPC had degression tendency in patients with coronary heart diseases, and PAI displayed opposite tendency. Conclusion The number of EPC were decreased and their function were impaired in patients with CAD, which may play an important role in the initiation and progression of CAD.