The application discloses a preparation method of a
stevia extract, and belongs to the technical field of
plant extract preparation; the preparation method comprises the following steps: S1, crushing stevia raw materials, then soaking the stevia raw materials in water, adding a composite
enzyme to perform enzymolysis, and preparing an enzymolysis solution; S2, performing
flocculation treatment on the enzymolysis solution; the flocculating agent is a composite flocculating agent, and a crude extract solution is obtained; S3, performing
gradient elution on the crude extract solution after adsorption by using a
macroporous resin, and collecting eluate of a specific section; and S4, performing
elution after adsorption of the eluate by using an aluminum
oxide column, concentrating the eluate, and crystallizing; the preparation method only uses water and
ethanol as solvents in the whole process, does not use toxic organic reagents, is simple to operate, and is very suitable for industrial
mass production.