The present invention discloses a preparation method for an amphiphilic nanosheet. The preparation method comprises the following steps: mixing choline chloride and urea, and heating to prepare a choline chloride-urea based deep eutectic solvent; adding styrene, divinylbenzene and azobisisobutyronitrile into a higher alkane solvent, stirring and dissolving to obtain an oil phase solvent, wherein an addition amount of the divinylbenzene is greater than 5% by mass of a styrene monomer; and adding a hydrophilic monomer, cetyltrimethylammonium chloride and the oil phase solvent into the deep eutectic solvent, stirring and mixing, ventilating and deoxidizing, then heating to 70° C., reacting for at least 6 h, and then crushing and centrifuging to obtain the amphiphilic nanosheet. According to the present invention, a block polymer does not need to be prepared in advance, and a hydrophobic monomer and a hydrophilic monomer are physically isolated, so that the prepared amphiphilic nanosheet has a distinct partition and is not easy to agglomeration. The method is similar to conventional emulsion polymerization, the amphiphilic nanosheet is prepared by a one-step method, and the preparation process is simple; and the method has high product yield and is easy for mass production.