Myricetin (MY) is a natural antioxidant flavonoid with a variety of biological activities. However, extremely low water solubility, bioavailability, and easy degradation, restrict their application. Recently, increasing interest in starch nanoparticles as a new kind of biocompatible renewable polymer in applications like nanocarriers. This work was to fabricate MY adsorption onto tapioca starch nanoparticles (TSNPs) and evaluate their biological activities. The adsorption mechanism, loading amount, antioxidative capacity, and in vitro release of the loaded MY were also analyzed. The adsorption kinetics and adsorption equilibrium were best explained by a pseudo-second-order model and Freundlich isotherms, respectively. Based on the thermodynamic parameters, adsorption was found to be a spontaneous and exothermic process with a decrease in entropy. MY possessed a maximum equilibrium adsorption capacity of 453 ± 8.07 mg/g. Low cytotoxicity were obtained as described by methylene blue assay, and a sustained release of loaded MY was observed in stimulated gastric (pH 2.0) and intestinal (pH 7.0) fluids. Additionally, the rate of clearance of DPPH free radicals was increased by the adsorption of MY onto TSNPs, which was confirmed by the lower value of 50 % inhibitory concentration (IC50).