Introduction: For some patients whose LIMA cannot be used, surgeons have to choose other conduit materials to revascularize the LAD. This study was to explore the differences between SVG and LIMA used for LAD in terms of parameters measured by transit-time flow measurement (TTFM) and the early graft patency. Methods: A total of 374 patients who underwent CABG were included in this study. According to the strategy of the left descending artery (LAD) revascularization, 374 patients were assigned to two groups: a left internal mammal artery (LIMA)group(n=332) and a great saphenous vein (SVG) group (n=42). Results: Before propensity Score-Matched, compared with the LIMA-LAD group, the SVG-LAD group had a significantly higher MGF(37.85±23.28 vs 29.70±20.97ml/min, P=0.021),but a lower PI value (2.12±0.68 vs 2.65±1.01,P＜0.001).There was no significant difference between the two groups in terms of DF(P＞0.05). After 1:2 propensity Score-Matched, there were 114 patients were included (SVG-LAD 38, LIMA-LAD 76), there was no difference in the baseline data between the two groups. Compared with the LIMA-LAD group, the SVG-LAD group also had a lower PI value (2.07±0.63 vs 2.74±1.02,P＜0.001),and also a higher MGF(37.27±24.31 vs 29.92±21.92ml/min),but there was no statistically difference(P=0.109). There was no significant difference between the two groups in DF (P＞0.05). There was no difference among the two groups in patency rate(P=0.405). Conclusion: SVG-LAD has a higher MGF and a lower PI value than LIMA-LAD before PSM but just has a lower PI value than LIMA-LAD after PSM. There was no difference among the two groups in early patency rate.