The determination of multiple components is considered to be one of the key methods to control the quality of traditional Chinese medicine (TCM), because the clinical efficacy of TCM is derived from the synergistic action of multi-components. When simultaneously determining multi-components in TCM with multiple reference standards (MRS), the limited availability and high expense of various reference standards is a major obstacle. Currently, a practical method determining multi-components with a single reference standard (SRS) is needed to solve the problem, in which the contents of those components without reference standards can be calculated using relative conversion factor. In the present paper, both MRS and SRS methods were established for the simultaneous quantitative determination of seven bioactive flavonoids in Muhudie (MHD), the seed of Oroxylum indicum L., a traditional Chinese herb that has been used for centuries. Forty samples were assayed and data obtained from the two methods were compared, and no statistically significant difference was observed by a T-test (P > 0.05), thus, the SRS method can be applied for quality analysis of MHD. At the same time, a certain correlation was discovered between the contents of the bioactive components and the morphological character of MHD.