Abstract: This paper reported the effect of Heparin in treating 20 cases of angina pectoris. The result showed that the effects of Heparin were evident on relieving pectoris, reducing frequency of attacks, improving electrocardiogram and inhibiting PAgT and PAdT etc, and that the effects of treatment were better when the heparin was given in dosage of 100 mg per day than in dosage of 50 mg and 25 mg per day, by intramuscular injection.