A method for preparing a pharmaceutical composition for enhancing immunity and a pharmaceutical composition prepared according to the method. The method includes steps of: mixing ginseng ethanol extract with fruit and vegetable fermentation conversion solution to obtain a mixture, namely, the pharmaceutical composition for enhancing immunity; wherein the ginseng ethanol extract is prepared by a following step of: reflux extracting ginseng by ethanol aqueous solution for obtaining the extract, namely, the ginseng ethanol extract; the fruit and vegetable fermentation conversion solution is prepared by following steps of: mixing fruit and vegetable, lactobacillus acidophilus bacteria solution, bifidobactreium longum bacteria solution, lactobacillus delbrueckiisubsp. bulgaricus bacteria solution, streptococcus thermophilus bacteria solution with water, and then fermenting for obtaining a fermentation product, namely, the fruit and vegetable fermentation conversion solution.