This study aimed to determine the effect of nanoencapsulation on the physicochemical and functional qualities of functional drinks based on Java-tea. Polysaccharide C nanoparticles were prepared by ionic gelation method using compound D as crosslinker. The initial experiment was conducted to obtain particle size below 300 nm with low polydispersity index and suitable flavor. Polyssaccharide C nanoparticles-drink was then analyzed for its physicochemical and functional qualities. The result showed that the polyssacharide C nanoparticles-drink had z-average diameter size 223.4 nm, polydispersity index 0.183, and zeta potential 18.28 mV which had significantly effect on physicochemical and functional of functional drink based on Java-tea compared to non-nanoparticles-drink (increasing pH value (3.94), total dissolved solid (4.5 obrix), refractive index (1.3395), viscosity (17.83 cP), lightness (L=71.75), hue (a=-2.47), hedonic rating (5.27 of 9 scale), sweetness (11.28 of 15 scale), foam volume 415 ml; decreasing particle size, polydispersity index, saturation (b), the intensity of sourness, and bitterness). Measurements of antioxidant activity and inhibition of α-glucosidase by utilizing in vitro method might not shown a credible result. Polyssacharide C nanoparticles showed as a potential capability to improve functional drink based on Java tea.