Objective To evaluate the efficacy and mechanism of Guanxinping Tablet[tablet for coronary heart disease（CHD）]for CHD and angina pectoris（AP）.Methods Totally 66 cases of CHD and AP were randomized into treatment group and control group

with 33 in each.Both groups were given basic treatment.The treatment group was added with 1.2g of Guanxinping Tablet once and three times daily.The control group was added with 1.24g of Xinkeshu Tablet once and three times daily.The medication lasted for 4 weeks in both groups.The attack frequency and duration of AP were observed before and after treatment.The TCM pattern efficacy was scored.The levels of plasma endothelin（ET）and nitric oxide（NO）were detected.The AP efficacy

electrocardiogram（ECG） efficacy and comprehensive efficacy were analyzed.Results The total effective rate of AP efficacy

ECG efficacy and comprehensive efficacy was 87.9%

81.8% and 87.9% in the treatment group and 66.7%

60.6% and 66.7% in the control group

with a significant difference between groups（P<0.05）.The attack frequency and duration of AP and TCM pattern scores were significantly decreased after treatment in the treatment group（P<0.05or P<0.01）

with a significant difference between groups in the attack frequency of AP and TCM pattern scores（P<0.05）.The ET level was significantly decreased but the NO level was significantly increased after treatment in the treatment group（P<0.05or P<0.01）.There was significant difference in level of NO and ET between groups after treatment（P<0.05）.Conclusion Guanxinping Tablet can obviously relieve the TCM symptoms

shorten the duration of AP

reduce the number of attacks and improve the clinical efficacy.Its mechanism may be relevant to increasing NO level and decreasing ET level.