The aim of this study is to increase the functionality of rice starch by modifying matcha tea extract and to determine the effect on some physicochemical properties and starch digestibility. According to the data analyzed, treatment with matcha extract was effective in increasing the nutritional value of native rice starch. At the highest level of extract addition, total phenolic and flavonoid content reached 129.54 mg/100 g and 40.16 mg/100 g, respectively, as no phenolic or flavonoid content was detected in control. In addition, the highest DPPH and FRAP values were determined to be 296.62 μmol TE/100 g and 814.89 mg/100 g, respectively, at the highest extract addition level. Treatment with matcha extract significantly reduced the eGI of native rice starch from to 94.61 to 64.63, while resistant starch was increased from 0.90 to 33.43%. According to the physiochemical analysis, there was a positive correlation between the extract ratio and the water-holding capacity of rice starch due to the high hydrophilic capacity of the phenolic compounds. In addition, the solubility and swelling power of starch were increased by treatment with matcha extract, but high temperatures had a negative effect on these physicochemical properties.