The invention discloses a post-treatment method for polysulfone resin prepared by a solution method. The post-treatment method comprises the following steps that: (1) inert gas is filled into a reaction kettle to make the pressure inside the reaction kettle higher than the atmosphere pressure, and then is extruded out from nozzle holes in the lower part of the reaction kettle to form resin flow; (2) the resin flow enters coagulating batch through a drawing roller and coagulates while drawing in the coagulating batch under the action of the drawing roller to form threads; (3) the threads enter a granulator through a driving roller to be cut into resin particles; and (4) the resin particles are washed, cleaned and dried to form pure resin particles. According to the post-treatment method, the washing times can be reduced in the washing process, i.e. the post-treatment method can conform to the qualification standard, so that the energy consumption and cost are reduced. Meanwhile, according to the post-treatment method, the loss of the polysulfone resin in the post-treatment process is reduced, and the yield is increased, so that the packing density of the pure resin is greatly improved, and the resin particles obtained by the post-treatment can be directly used for injection, extrusion molding or modification.