Inflammation plays a pivotal role in coronary heart disease. Dendritic cells (DCs) are principal players in inflammation and atherosclerosis. Although the percentage of circulating DC precursors in coronary heart disease have been investigated, circulating myeloid DC (mDC) and plasmacytoid DC (pDC) precursors have not been extensively studied, particularly in relation to the severity of coronary artery lesions in patients with coronary heart disease. In this study, we recruited controls (n = 29), patients with stable angina pectoris (SAP, n = 30), patients with unstable angina pectoris (UAP, n = 56), and patients with acute myocardial infarction (AMI, n = 50). The severity and extent of coronary artery lesions was evaluated by Gensini score, following coronary angiograms. The percentage of circulating mDC and pDC precursors was determined by fluorescence-activated cell sorting (FACS). Plasma levels of MCP-1 and MMP-9, which correlate with atherosclerosis and DC migration, were also measured. The percentage of circulating mDC precursors was reduced in patients with AMI and UAP compared with control and SAP patients, respectively (p < 0.01 for AMI vs. SAP and Control, p < 0.05 for UAP vs. SAP and Control). The percentage of circulating pDC precursors was not significant changed. The levels of plasma MMP-9 and MCP-1 and Genisi score were all increased in patients with AMI and UAP, compared to control and SAP patients, respectively (p < 0.01 for AMI vs. SAP and control, p < 0.05 for UAP vs. SAP and control). Overall, the percentage of circulating mDC precursors was negatively correlated with MCP-1 (p < 0.001), MMP-9 (p < 0.001) and Genisi scores (p < 0.001). Genisi scores were positively correlated with the levels of MCP-1 (p < 0.001) and MMP-9 (p < 0.001). Our study suggested that the percentage of circulating mDC precursors is negatively correlated with the severity and extent of coronary artery lesions in patients with coronary heart disease.