NOVELTY - Diphenolic acid and composite alkali are mixed, inert composite solvent and water carrier are added, reacted and cooled. 4,4'-Dichlorodiphenyl sulfone is mixed with the resultant material, reacted, cooled, and precipitate is collected. The obtained precipitate is mixed with solution of diluted hydrochloric acid and tetrahydrofuran, precipitated and filtered, to obtain white polymer. The obtained polymer is dissolved in tetrahydrofuran, filtered, and the resultant filter cake is collected. The filter cake is boiled with water, filtered, and dried, to obtain poly(aryl ether)sulfone.    USE - Preparation of poly(aryl ether sulfone) used in preparation of adsorbent for absorbing divalent copper ion in water treatment (all claimed), separation membrane and fuel cell.    ADVANTAGE - The method provides poly(aryl ether sulfone) having high glass transition temperature and excellent thermal stability, mechanical property, recyclability and film-forming effect. The adsorbent prepared using the poly(aryl ether sulfone) has divalent copper ion absorbing rate of more than 90%.    DETAILED DESCRIPTION - Diphenolic acid and composite alkali are added into a reactor, mixed, inert composite solvent and water carrier are added, mixed uniformly for 1-4 hours and reacted at 130-160 degrees C for 2-3 hours, and the resultant reaction product is cooled to room temperature. 4,4'-Dichlorodiphenyl sulfone is added and mixed with the resultant material at 130-160 degrees C for 2-3 hours, the temperature is the resultant mixture is increased to 160-200 degrees C, reacted for 5-24 hours, the resultant reaction solution is cooled to room temperature and precipitate is collected. The obtained precipitate is mixed with mixed solution of diluted hydrochloric acid and tetrahydrofuran in volume ratio of 1:0.5-1.5, deionized water is added, mixed at 100 degrees C, precipitated and filtered, to obtain white polymer. The obtained polymer is dissolved in tetrahydrofuran, to obtain polymer solution, hot ethanol is added, stirred, filtered, and the resultant filter cake is collected. The obtained filter cake is boiled with deionized water for 3-5 times for 2 minutes, filtered, and the resultant filter cake is dried under vacuum at 100 degrees C for 12-24 hours, to obtain high-molecular weight poly(aryl ether)sulfone. The molar ratio of diphenolic acid, 4,4'-dichlorodiphenyl sulfone and composite alkali is 1:1:1.5-2.5.