Aim To analyze correlation between the N-terminal brain natriuretic peptide precursor （NT-proBNP） levels and severity of coronary artery disease in patients with acute coronary syndrome （ACS）. Methods 40 patients was diagnosed with ACS combined coronary angiography and history,replacement of the 20 cases in the control group was coronary angiography negative. Gensini score was used for the evaluation of coronary lesions severity. According to Gensini score,ACS patients were divided into the Gensini score ≥30 group and <30 group. And according to the number of diseased vessels,ACS patients were divided into single,double and three vessels disease groups. Immunoassay analyzer and ancillary reagents were used for determination of plasma NT-proBNP level in all patients. The correlation between NT-proBNP levels and the severity of coronary artery disease was analyzed. Results NT-proBNP levels of ACS group were significantly higher than that in the control group ［242.56 ± 68.16 ng/L vs 27.12 ± 16.48 ng/L,P<0.01］. The level of NT-proBNP in three-vessel disease group was higher than in single-vessel disease group （P<0.05）. In Gensini score ≥30 group,NT-proBNP level was significantly higher than that in Gensini score <30 group ［228.14 ± 46.16 ng/L vs 127.64 ± 32.64 ng/L,P<0.05］. Plasma NT-proBNP level was positively correlated with the Gensini score （r0.56,P<0.05）. Conclusions Plasma NT-proBNP levels in patients with ACS has clinical significance in the evaluation of coronary artery disease severity.