Aims. Local IGFBP1 level was reported to affect the development of coronary artery plaque. This study investigated the association of circulating IGFBP1 level with the severity of coronary artery lesions in patients with unstable angina. Materials and Methods. In 112 consecutive patients with clinically diagnosed unstable angina, admitted from July 2014 to July 2015, we studied the correlations of circulating IGFBP1 and the severity of coronary artery disease (CAD). Results. All patients underwent scheduled coronary angiography, and 67 cases were diagnosed with critical and 45 with noncritical CAD. Of the 67 critical CAD patients, 41 (61.19%) presented with multivessel and 26 (38.81%) with single-vessel lesions. IGFBP1 levels were higher in patients with multivessel than those with single-vessel lesions. Moreover, the IGFBP1 level was positively correlated with the GRACE score. Among clinical variables, the IGFBP1 level was correlated with HDL-C. IGFBP1 alone (cutoff 20.86 ng/ml) demonstrated a sensitivity of 0.448 and specificity of 0.933 in predicting CAD. Combination of IGFBP1 and HDL-C had a sensitivity of 0.821 and specificity of 0.800 in predicting CAD. Conclusions. Circulating IGFBP1 level positively correlated with the severity of CAD. IGFBP1, when combined with HDL-C, might be useful in screening for high risk CAD patients.