A variety of traditional Chinese medical formulations contain two or more herbs from the same genus or family. Although these herbs may have a similar appearance and constituents, they usually have different pharmacodynamic actions. A series of qualitative and quantitative analysis methods are developed to determine one or more compounds for quality control of medicine. As far as we know, no method has been found to determine the real ratio of the two herbs along with the prescription. In this study, we used HPLC-DAD as a way to determine the content of Moutan cortex (M) and Paeoniae radix alba (P) in GuizhiFuling Wan (GZFLW). An effective, accurate and reliable HPLC-DAD method was developed for detecting the content of M and P in GZFLW through the analysis of four monoterpeneglycosides, namely, galloylpaeoniflorin (1), paeoniflorin (2), mudanpioside C (3) and benzoylpaeoniflorin (4). Due to the different UV characteristics of the compounds, the detection wavelength was 270 nm for 1 and 2, while 3 and 4 were monitored at 254 nm and 230 nm, respectively. Four equations were put forward to describe the relationship between content of M as well as P and the four monoterpene glycosides in GZFLW. After validation, all the accuracies of the M and P contents in GZFLW were within 10%. The result showed that the method could be successfully applied to analyze the contents of M and P in GZFLW. Moreover, our method may be more widely used to control the quality of proprietary Chinese medicines, especially for those containing the same genus or family herbs, in industrial GMP production.