ObjectiveBy starting with the combination of Os Draconis， Bupleuri Radix， and Ostreae Concha， the role of mineral medicine Os Draconis in the combination of the Bupleuri Radix-containing tri-herbal medicines was preliminarily explored from the perspective of supramolecular system formation. Method① The appearance and Tyndall phenomenon of single decoction of Os Draconis， Bupleuri Radix， and Ostreae Concha， as well as co-decoction of Bupleuri Radix-Os Draconis， Bupleuri Radix-Os Draconis-Ostreae Concha， and Bupleuri Radix-Ostreae Concha were observed， and the average particle size， dispersion coefficient， and Zeta potential of suspension particles in each decoction were determined. The micromorphology of supramolecular structures was observed by scanning electron microscope （SEM）. ② The pH of different compatibility systems， liquid viscosity coefficient， liquid surface tension， freeze-dried powder yield rate， and other physical properties were determined， and the interaction of different compatibility systems was detected by infrared absorption spectroscopy （FTIR） and UV-visible spectrophotometry （UV-Vis）. ③ The composition and content difference of different compatible systems were determined by high-performance liquid chromatography （HPLC） and ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry （UPLC-Q-TOF-MS）. ResultCompared with the single decoction， the co-decoction had more obvious turbidity and Tyndall phenomenon. The particles in the co-decoction suspension were smaller and more evenly distributed， and the Zeta potential was reduced， indicating a more stable system. Under SEM， Bupleuri Radix was irregularly lamellar， and Bupleuri Radix-Os Draconis and Bupleuri Radix-Os Draconis-Ostreae Concha were mainly spherical nanoparticles. Bupleuri Radix-Ostreae Concha was irregularly lamellar， with a small number of spherical nanoparticles. The pH of the single decoction of Bupleuri Radix and co-decoction increased， and the viscosity coefficient increased. The liquid surface tension decreased. The freeze-dried powder yield rate of the Bupleuri Radix-Os Draconis co-decoction was the highest， followed by Bupleuri Radix-Ostreae Concha decoction and Bupleuri Radix-Os Draconis-Ostreae Concha decoction， and the yield rate of Bupleuri Radix single decoction was the lowest. The main change of FTIR was the stretching vibration of -OH， and the co-decoction moved to the low-frequency direction obviously. UV-Vis showed that the maximum absorption occurred at 295.8 nm for all groups， and the absorption intensity was different （Bupleuri Radix-Os Draconis>Bupleuri Radix-Os Draconis-Ostreae Concha>Bupleuri Radix-Ostreae Concha>Bupleuri Radix）. The components of Bupleuri Radix were used as the indexes， and the content of methanol extract determined by HPLC was higher than that of water extract， and the components of Bupleuri Radix single decoction were mainly saikosaponin a （SSa） and saikosaponin c （SSc）， which were slightly higher after co-decoction compatibility. UPLC-Q-TOF-MS could identify 37 compounds in both single decoction and co-decoction. ConclusionThe combination of Bupleuri Radix， Os Draconis， and Ostreae Concha can form a smaller， more uniform， and stable nano-sized supramolecular system， which is conducive to the dissolution of the main components of Bupleuri Radix， and the Os Draconis contributes the most in this process.