Objective To investigate the therapy with Trimetazidine on Endothelial cell in patiens with coronary heart disease. Methods 50 patiens with with coronary heart disease were divided at random into 2 groups: Trimetazidine group and contrust group. The contrast group administered routine thearapy, the Trimetazidine group take Trimetazidine orally, 20mg per day at 3 meals. Compared the two groups in aspect of the times of angina pectoris attacked, lasting time, change of EKG. The plasma CEC and ET-1 levels were also determined before and after treatment, and compare them. Results After the treatment, both the improvement of angina pectoris attacked, lasting time, change of EKG were 98% and 76% respectively. Compared with that of cont rast group, the difference is significant (P< 0.05). CEC and ET-1were lower in cases of Trimetazidine group than those of routine group (P < 0. 05) after the treatment. Conclusion Trimetazidine could improve clinical symptom of patiens with coronary heart disease by protecting endothelial cell.