SimiaoYong'an decoction, a traditional Chinese medicine formula consisting of four herbs, has been widely used for the treatment of gangrene disease. However, its clinical application is restricted due to the lack of an effective quality control method that covers the main active compounds in the formula. In this study, a high-performance liquid chromatography with diode-array detection (HPLC–DAD) method was established for the simultaneous determination of 13 active compounds including harpagide, neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, ferulic acid, isochlorogenic acid B, isochlorogenic acid A, isochlorogenic acid C, angoroside C, harpagoside, cinnamic acid, glycyrrhizic acid, and ligustilide. Separation of these compounds was achieved using a Kromasil 100-5-C18 column with a gradient elution program consisting of acetonitrile and 0.4% phosphoric acid solution. The specificity, linearity, precision, repeatability, and accuracy tests were implemented to validate the method. The validated method was successfully applied for determination of 13 components from several finished batches of SimiaoYong'an decoction. The results demonstrated that the established method was accurate, reliable, and could be used as a suitable quality control method for the quantification of SimiaoYong'an decoction.