The release of various substances before and after in vitro di-gestion of ultrafine green tea powder was measured.The results showed that the release of free amino acids, total phenols, total flavones and most catechins declined during the in vitro digestion of ultrafine green tea powder; caffeine remained un-changed; The release of soluble protein, gallic acid, catechin gallate, gal-locatechin, gallocatechin gallate, and isoquercetin increased. The non-extractable polyphenols were released. Brewing and drinking ultrafine green tea powder are beneficial to improve the comprehensive utilization of tea by the human body.