The present invention relates to a method for processing an acetic acid solvent in crude terephthalic acid (CTA) in an oxidation unit of a pure terephthalic acid (PTA) industrial device. In the present invention, a filter cake in CTA is washed by means of a "two-stage, three-step" method, while the present invention further shortens the production process of solvent exchange technology of CTA pressure filters, improves the production capacity of a device, reduces the costs of the device, reduces the energy consumption of a system, and solves the shortcomings of the existing CTA solvent exchange technology of pressure filtration filters.