Preparation method and application of anti-soil polymer

The invention provides a preparation method and application of an anti-soil polymer. The prepared polymer is used as a dispersant for a hydraulic cementing agent and/or an aqueous dispersion for potential hydraulic cementing agent and has good anti-soil performance. The preparation method the anti-soil polymer comprises a step of subjecting polyether macromonomer A with a special structure, monomer B containing a phosphoric acid or phosphorous acid group, optional monomer D and aldehyde C to condensation polymerization so as to prepare the anti-soil polymer, wherein the monomer D is selected from the group consisting of phenol, aniline, p-/o-aminobezene solfonic acid, p-/o-hydroxybenzoic acid, p-/o-aminobenzoic acid, p-/o-hydroxyezene solfonic acid, p-/o-toluidine and p-/o-methylphenol, a mol ratio of the polyether macromonomer A to the monomer B to the monomer D is 1: (0.5-12): (0-8.0), and a mol ratio of the polyether macromonomer A to the monomer B and the monomer D is 1: (0.5-12.0).