The invention belongs to the field of thermotropic liquid crystal ionomer copolyester and synthesis preparation and especially relates to a thermotropic liquid crystal ionomer beta nucleating agent containing a sulfonate group and a preparation method and application thereof. The preparation method comprises the following steps: mixing dimethy-5-sulfoisophthalate sodium salt and biphenyldioxohexanol under the action of a catalyst and heating and stirring for a reaction; adding phenylsuccinic acid, heating and vacuumizing and continuously conducting a reaction, and cooling after the reaction. By the use of the thermotropic liquid crystal ionomer beta nucleating agent containing the sulfonate group for modification of polypropylene, content of beta-crystal in the polypropylene matrix is increased, and a stable nucleation center can be formed from the liquid crystal ionomer at low molecular weight.