To develop the polymerization exploiting the interconversion of fluorinated carbon radical to hydrocarbon radical, the radical cyclopolymerization of perfluoroisopropenyl vinylacetate [CF2=C(CF3)OCOCH2CH=CH2] (FIA) was investigated to afford a polymer possessing mainly five-membered ring structure with bimodal molecular weight distribution having 1 x 10(5) as the higher molecular weight. This may be the first example wherein the cyclopolymerization between usual allyl group and fluorinated vinyl group is performed. The degree of cyclization was between 70 and 80% determined by F-19 NMR of as-polymerized products. The polymer preparation from perfluoroisopropenyl group, which shows scarce homopolymerization reactivity was accomplished. The mechanism that the addition of hydrocarbon radical to perfluoroisopropenyl group to produce fluorinated carbon radical followed by the intramolecular addition reaction onto allyl group to form five-membered ring is proposed. The hydrolysis of the FIA polymer afforded a polymer possessing hydrophobic fluoroalkyl group with hydrophilic hydroxyl and carboxylic acid groups.