The invention discloses a green preparation method of high-purity tea saponin, and relates to the field of tea saponin extraction. The invention provides the green preparation method for high-purity tea saponin in view of the problems of low extraction rate and poor purity in the current tea saponin extraction process, wherein the preparation method includes the following steps: (1) raw material pretreatment: crushing oil tea seed meal, and allowing to pass through a 20 mesh-80 mesh sieve, to obtain oil tea seed meal powder; (2) adding an organic solvent into the oil tea seed meal powder obtained in the step (1) according to the ratio of material to liquid of (1 g:6 mL)-(1 g:15 mL), and mixing, wherein the organic solvent is a mixed solvent of polar and non-polar solvents; (3) carrying outheat preservation of the material-liquid mixture of the step (2) for 3-6 h at the temperature of 50-100 DEG C; and (4) carrying out solid-liquid separation, and drying a precipitate precipitated after cooling the obtained liquid, to obtain tea saponin. The green preparation method is suitable for extraction and industrialized production of tea saponin.