Abstract: Polyether sulfone ultrafine powder having a particle size larger than 0.1 ?m and smaller than or equal to 5 ?m and a coating having the ultrafine powder added thereto are disclosed. The polyether sulfone ultrafine powder is easy to be mixed uniformly with other materials and has better flowing property and higher affinity for water, is unlikely to be clustered in a solvent, and is stable in performance after being dissolved. In addition, less organic solvent would be used when the coating is prepared. Besides, when the polyether sulfone ultrafine powder is used as plastic and glass modifiers, the surface finish of the obtained plastic plates and glass products is improved.