The present invention provides a special fruit detergent preparation method, which comprises: weighing cassava starch to a proper amount of water, adding 0.1 mol/L sodium hydroxide to adjust the pH value to about 8, adding castor oil and an appropriate amount of sorbitol fatty acid ester, carrying out stirring dissolving, adding a mixture of polyethylene glycol 600 and glycerin (4:1), carrying out a reaction for a certain time, standing, carrying out centrifugation, washing, drying to obtain light yellow starch microspheres, and uniformly mixing 30-90% by mass of the starch microspheres, 5-10% by mass of sodium chloride, and a proper amount of water to obtain the detergent. According to the present invention, the starch microsphere technology is adopted to prepare the nature detergent, chemical surfactants and detergent components do not exist, the detergent is pure nature, and starch has an unique absorption characteristic so as to effectively remove difficultly cleaning fruits; and the raw materials are easy to obtain, the cost low, the price is low, and the method is suitable for commercial promotion use.