Objective:To investigate the factors affect on fractional flow reserve(FFR),and to evaluate the value of FFR in guiding stenting. Methods:Sixty patients with coronary heart disease and hospitalized in the department of cardiology of the First People’s Hospital of Zhangjiagang City from February 2012 to January 2015 were retrospectivly enrolled,including patients with chest tightness and chest pains,suffered acute myocardial infarction and those who underwent coronary angiography again after stenting. General data such as age,gender,smoking history and the levels of low-density lipoprotein-cholestero l(LDL-C),total cholesterol(TC),triglyceride(TG)and blood glucose(BG)were recorded. All patients underwent coronary angiography and FFR measurement. The degree of stenosis and length were recorded. Patients were divided into two groups:FFR≥0.8 and FFR<0.8. General data were compared between the two groups,and the correlations with FFR were analyzed. Stents were implanted only when the FFR<0.80,and FFR were measured again when stenting were finished. We compared FFR before and after stenting. The numbers of readmission for cardiac causes,a new episode of angina,revascularization of the target lesion,arrhythmia,heart failure and acute myocardial infarction were recorded and compared between the two groups in the first year. Results:①All of the 60 patients had completed coronary angiography and FFR measurement. There were no differences of general data between the FFR≥0.8 group and the FFR<0.8 group. There were significant differences of degree of stenosis and the length of stenosis between the two groups(both P < 0.001),and there were significant negative correlations between FFR and degree of stenosis and the length of stenosis(P < 0.001).②In patients with FFR<0.8,there were significant differences in FFR before and after stenting(P < 0.001). There was no difference of FFR between patients after stenting in the FFR<0.8 group and those in the FFR≥0.8 group(P=0.085).③The numbers of LAD,RCA and LCX belonged to different degree of stenosis were calculated,and there were no differences of FFR in the same degree of stenosis in different coronary artery(P > 0.05). ④During one-year follow-up,there was no difference of a new episode of angina,revascularization of the target lesion,arrhythmia and heart failure between two groups(P > 0.05). There was no acute myocardial infarctions event at 1 year in both groups. Conclusion:There were significant negative correlations between FFR and the degree of stenosis and the length of stenosis. This indicates that the more severe of stenosis and the longer of stenosis length,the more significant influence on the functional repercussion of coronary. FFR measurement is useful in guiding PCI treatment and evaluating the value of stenting.