Polymer-supported organoselenium reagents with amide linker were readily prepared from substituted-polystyrene resins. Through the use of polymer-supported arylselenenyl bromides, the oxyselenenylation reaction of olefins was carried out even in water. An amphiphilic polymer-supported arylselenenyl bromide was employed, and the intramolecular oxyselenenylation and the subsequent deselenenylation reactions proceeded smoothly in water with fair chemical yields (up to an 83% total yield).