The invention discloses a preparation method of a pineapple and orange composite ferment beverage. The preparation method comprises the following steps of step I, separately taking raw materials of fresh pineapples and oranges, performing peeling, performing separate dicing and performing uniform mixing so as to obtain fruit raw materials; step II, taking
fungus powder, and adding pure water for diluting so as to obtain
fermentation fungus water; step III, adding the
fungus water to the fruit raw materials until the level of the fungus water exceeds the surfaces of the fruit raw materials, then performing sealing, loading the fruit raw materials and the fungus water, which are sealed, in an
incubator for
fermentation, after
fermentation, taking out the fermented fruit raw materials and the fermented fungus water, performing filtering so as to obtain a ferment
stock solution, and placing the ferment
stock solution in a refrigerator for after-
ripening so as to obtain ferment liquid; step IV, adding honey, pure water and white granulated
sugar to the obtained ferment liquid obtained in step III, performing uniform mixing, then adding
vitamin C and beta-
carotene, and performing homogenizing so as to obtain the pineapple and orange composite ferment beverage. The prepared composite ferment beverage is delicately fragrant in smell, fine and smooth in mouth feel, and moderate in sour and sweet degrees, and the activity of
superoxide dismutase (SOD) contained in the composite ferment beverage achieves 100-150U / g.