The invention relates to a method for preparing a strongly-stable liquid viscoelastic magnetic abrasive tool material, and belongs to the technical field of abrasive tool materials. Humic acid is usedas a modified material, modified polyacrylic acid has strong thickening and adsorption ability, carboxyl groups in a molecular chain can be reacted with a small amount of hydroxyl groups and silane groups on the surface of solid phase particles to form chemical bonds, and in addition, polyacrylic acid molecules can also act on the surface of carbonyl iron powder particles by hydrogen bonds. Through combined effectof the two adsorption modes, the polyacrylic acid molecules can be adsorbed to the surface of the solid phase particles by the chemical bonds and the hydrogen bonds, so that one endsof the polyacrylic acid molecules can be pinned on the surface of the solid phase particles, the other ends of the polyacrylic acid molecules can be dispersed in a solvent, in an alkaline solution, the polyacrylic acid molecules adsorbed on the surface of the solid phase particles can be ionized to obtain negatively charged R-COO-groups, the negative charge density of the surface of the solid phase particles is increased, and the surface potential of the particles is increased, and the stability of an abrasive tool can be improved.