Abstract: The photosensitive monomer cinnamic acid (CA) was introduced into hyaluronic acid (HA) to prepare amphiphilic HA-CA. HA-CA colloidal particles were obtained through self-assembly in selective solvents H₂O/DMSO. The structure and the modification degree of HA-CA were confirmed by ultraviolet spectroscopy (UV) and proton nuclear magnetic resonance (¹H-NMR). The self-assembly behavior of HA-CA was investigated. The size and morphology of the HA-CA colloidal particles were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and Zeta potential analyzers. HA-CA colloidal particles were used as particulate emulsifier to stabilize oil-water interface and the emulsification performance of HA-CA colloidal particles in different conditions, such as pH value, salt concentration and the oil type, was investigated. The morphology of colloidal particles on the oil-water interface was observed by styrene oil phase solidification method. The cell compatibility of colloidal particles and emulsions were also studied. Results show that HA-CA has absorbance in the range of 250~320 nm. HA-CA can self-assemble into spherical colloidal particles with the size of about 95 nm in selective solvent. HA-CA colloidal particles could be used as particulate emulsifier to prepare oil-in-water Pickering emulsion in the broader range of pH and various concentrations of NaCl. Although HA-CA colloidal particles can not stabilize the oil-water interface to form stable emulsion when pH is 6.47, adding a little inorganic salt can greatly improve HA-CA colloidal particle's emulsifying capacity in neutral condition. In addition, the colloidal particles as well as emulsions have great salt tolerance and cell compatibility. Moreover, HA-CA colloidal particles can also stabilize a wide range of oil-water system, which means it has a certain universality as a particle emulsifier.