Objective:To probe into the mechanism and application prospect of modified Renshen Decoction for treatment of deficiency-cold type precordial pain due to obstruction of Qi in the chest.Methods:60 cases of precordial pain due to obstruction of Qi in the chest were randomly divided into a treatment group（n=30）treated by oral administration of modified Rensben Decoction

and a control group（n=30）treated by oral Compound Danshen Tablet.4 weeks constituted one course.Paroxysm times of angina pectoris

dosage and times of nitroglycerinum

cumulative score of the pain syndrome

the time of medicine producing action and the lasting time of the medical action were recorded

and electrocardiogram（ECG）

blood lipids

hemorheological indexes before and after treatment were detected.Results:There were significant differences between the two groups in total effective rates for alleviating angina pectoris

precordial pain

improvement of ECG

and the time of medicine producing action and the lasting time of medical action（P<0.05 or P<0.01）.There were very significant differences in blood lipids and hemorheological indexes of the treatment group before and after treatment（P<0.01）

and after treatment there were significant differences between the two groups in blood lipids and hemorheological indexes（P<0.01）.Conclusion:Modified Renshen Decoction has significant therapeutic effects in relieving angina pectoris

improving precordial pain

with fast and longer-lasting action

and it has significant actions of improving ECG

blood lipid

hemorheological indexes.