Salvianolic Acid B (Sal B) is one of the main medicinal ingredients of Radix Salvia miltiorrhiza (Danshen) and possesses a variety of pharmacological effects. The purpose of this study was to discover the new mechanism of action of Sal B based on the protein interaction network (PIN) analysis. A PIN of Sal B was constructed with 852 nodes and 8,626 interactions. By fast agglomerate algorithm based on the edge clustering coefficients (FAG-EC), 11 modules were detected from the network. Gene ontology (GO) enrichment analysis of the modules demonstrated that the roles of Sal B played in cardiovascular disease were related to multiple biological processes, which could represent the characteristics of Chinese Material Medica (CMM) as a whole to regulate the disease. The most interesting finding of this work was that the anti-inflammatory effect of Sal B was due to the immune response of T lymphocytes by regulating IL-2 family, CD3E, CD79A, MAP3K7 and PRKCQ. Therefore, the module-based network analysis will be an effective method for better understanding CMM.