The systematic and unbiased charting of protein-protein interaction (PPI) networks relevant to health or diseases has become an important and burgeoning challenge in systems biology. Further, current reports have supported that good correlation exists between the topological properties and biological function of protein nodes in networks. Coronary artery disease (CAD, also called coronary heart disease) is the most common type of heart disease worldwide. Traditional approaches of studying individual gene or protein have shown their weakness in such complex disease. Here, we provide NetCAD, a web-based tool for systematic investigation of CAD-specific proteins in human PPI network. The features of NetCAD includes the following: proposing a novel method combining biological principles and graph theory, quantified topological analysis tools, build-in PPI information database consolidated from major public databases, creating CAD-associated subnetwork and visualizing network graph with good visual effects. NetCAD may provide important biological information for uncovering the molecular mechanisms and potential targets for therapies of CAD, which could not be found merely through molecular biology methods.