The invention provides a magnetorheological polishing adhesive and a preparation method thereof. The magnetorheological polishing adhesive is composed of carbonyl iron powder (30%-70%), polishing powder (2%-7%), gel (0.5%-5%), gas-phase silicon dioxide (0.2%-1.5%), deionized water (10%-35%), and glycerol (15%-40%). The preparation method comprises the following steps: (1) weighing the carbonyl iron powder, the polishing powder, the gas-phase silicon dioxide, the gel, the deionized water and the glycerol according to a formula of the magnetorheological polishing adhesive; (2) putting the glycerol and the deionized water into a container, performing stirring to obtain a glycerol aqueous solution, performing heating, dissolving the gel into the glycerol aqueous solution under stirring to forma mixed solution; (3) adding the weighed carbonyl iron powder, the weighed gas-phase silicon dioxide, and the weighed polishing powder to the mixed solution in sequence, and performing stirring to obtain a magnetorheological polishing adhesive; and (4) putting the formed magnetorheological polishing adhesive into a refrigerating chamber, performing refrigeration, and taking the adhesive out whenusing. The magnetorheological polishing adhesive provided by the invention has the simple preparation method, higher stability and a higher shear yield stress, and can meet performance requirements ofprocessing.