The invention discloses a benzene sulfonic amide hydroxyl derivative as shown in a formula 5 and a preparation method thereof as well as the application of a compound 5 of <18>F as a PET imaging molecular probe. The compound has favorable suppressive activity of carbonic anhydrase, stronger hydrophilicity and little collection and little nonspecific absorption in a digestive system of a human body. The preparation method of the compound adopts simply and easily obtained raw materials and simple preparation method and has no particular requirements for high-temperature, high-pressure or sensitive reagents. The invention also discloses a intermediate compound as shown in a formula 4 used in the preparation method of the compound and the preparation method thereof.