A phase transfer catalyst library with 50 kinds of polystyrene-supported quaternary ammonium salt catalyst was synthesized by the reaction of 10 kinds of chloromethylated crosslinked polystyrene with five tert-amines using the portioning-mixing method. The Br/I anion exchange reaction of hexyl-bromide and borohydride reduction of acetophenone were used as the probing reactions to screen out the most active catalysts for each reaction using the iterative deconvolution method. For the Br/I anion exchange reaction of hexyl-bromide, the catalytic activity of the phase transfer catalyst was mainly affected by the lipophilicity of the active sites, and the most active catalyst was a macroporous strongly basic anion exchange resin (1). However, for the borohydride reduction of acetophenone, a gel-type (microporous) strongly basic anion exchange resin (2) was the most active catalyst, and a hydrogen bonding promoted catalytic mechanism was proposed to explain the high catalytic activity of the catalyst.