Preparation method of low-caffeine tea extract

A preparation method of low-caffeine tea extract disclosed in the invention relates to a preparation method of theacea plants extract, comprising the following steps: (1) tea is crushed into tea powder, and a humidification pretreatment is carried out onto the tea power; (2) the treated tea powder is extracted by a supercritical carbon dioxide extraction method; (3) the tea powder extracted by supercritical fluid extraction is extracted by a water-bath method; and (4) the extract is filtered, then concentrated and freeze dried. According to the invention, active substance in tea can be extracted effectively, the content of caffeine in the active substance can be controlled to no more than 3% (quality percentage content), and the tea extract can inhibit the growth of tumor cells with high efficiency. Experiments verify that the active substance has low side effect and good inhibition effect of the growth of tumor cells, without drug resistance.