Abstract: In order to analyze the stability of natural emulsion formed by chitosan and the effect of nano SiO₂ addition on its properties, CS−nano SiO₂ composite emulsions were prepared by using nano SiO₂ modified chitosan as the aqueous phase and camellia oil as the oil phase. The effects of different amount of nano-SiO₂(1.00%, 3.00%, 5.00%, 7.00% and 9.00%) on CS−nano SiO₂ composite emulsion were studied by the characteristics of emulsifying activity, emulsifying stability, centrifugal stability, average particle size and rheological properties. At the same time, the microstructure and surface morphology were evaluated by particle size distribution, electron microscope and optical microscopy analysis. The results showed that the physical and chemical properties of the composite emulsion were improved, and showed higher stability compared with CS emulsion. At 5.00% of nano-SiO₂, the comprehensive properties of emulsions were better than that of control samples. The physicochemical properties of composite emulsions were improved compared with CS emulsion, the emulsifying activity from 9.29 to 10.36 m²/g, which increased 10.37%, and the emulsifying stability increased by 10.53% from 484 min to 541 min. The Ke decreased by 54.56%(P<0.05). The mean particle size was 12.98 μm. The particle size distribution was narrow and the peak value was high. The emulsion viscosity, the storage and loss modulus increased, and the emulsion appeared gelatinous. Scanning electron microscope and optical microscope observation showed that the emulsion had uniform distribution and uniform appearance.