The invention discloses lignin-based amphiphilic azo-polymer colloidal spheres as well as a preparation method and application thereof. The preparation method comprises the following steps of: dissolving alkali lignin in a NaOH solution with pH of 8-14, dropwise adding a hydrogen peroxide solution with the mass concentration of 25%-35% under the condition of a 85-95 DEG C water bath, after reacting for 0.5-1.5 hours, and cooling to a room temperature to obtain the alkali lignin without methoxyl; preparing diazonium salt; mixing the alkali lignin without methoxyl with the diazonium salt, adding an alkalinity conditioning agent to adjust pH to 8-14, after reacting, adding an acidity conditioning agent to adjust pH of the solution to 1-4, so that products are acidified out and precipitated, washing precipitates by deionized water, after drying, taking out, dissolving the products in an organic solvent, and adding water serving as a precipitator to obtain the lignin-based amphiphilic azo-polymer colloidal spheres. The solid content of ceramic slurry prepared from the lignin-based amphiphilic azo-polymer colloidal spheres disclosed by the invention reaches up to 70.9wt%-73.1wt%, and is far higher than that of blank slurry; and compared with a conventional dispersion agent, the lignin-based amphiphilic azo-polymer colloidal spheres have a better dispersion effect.