This research was conducted by right of adopting anti-solvent method to prepare two kinds of water-soluble β-carotene nanoparticles and conducting the research of its physicochemical properties and in vitro digestive characteristics based on the materials of whey protein nanofibrils and two polysaccharides including inulin and hyaluronic acid. The results showed that the Zeta potential of the WPN/Inu/BC and WPN/HA/BC were （+48.27±0.65） mV and （+44.83±0.8） mV as well as the encapsulation efficiencies were （94.34±1.35）% and （99.02±0.17）%， respectively； the DPPH free radical scavenging activity were （61.20%±2.08）% and （68.85%±1.84）% and the half-lives of BC in WPN/Inu/BC and WPN/HA/BC composite particles were 15 d and 16 d， respectively. Fluorescence spectra showed that whey protein nanofibrils compounded with polysaccharides were exposed more hydrophobic groups to better compound with BC. Fourier-transform infrared spectroscopy indicated that some absorption peaks of polysaccharides and β-carotene shifted， suggesting the formation of interaction among whey protein nanofibrils． In vitro simulated digestion experiments show that WPN/polysaccharide/BC composite particles had good controlled release ability.