The invention discloses an anti-settling aid, and a preparation method and application thereof. The preparation method comprises the following steps: generating a functional monomer B from sultone, afunctional monomer A and a small amount of polymerization inhibitor at a certain temperature; adding the obtained functional monomer B and neutral monomer acrylamide into a certain amount of sodium chloride solution, and carrying out a copolymerization reaction under the action of an initiator to obtain a zwitterionic copolymer; and carrying out co-heating on the zwitterionic copolymer and an aqueous cross-linking agent solution in a hydrochloric acid solution for a cross-linking reaction so as to obtain an amphoteric micro-cross-linked polymer. Based on reverse polyelectrolyte effect and micro-crosslinking effect, the amphoteric micro-crosslinked anti-settling aid applicable to wet-ground concrete waste slurry high-salt system is developed; and compared with the prior art, the amphotericmicro-crosslinked anti-settling aid has remarkable beneficial effects.