A well-defined linear polystyrene with cyclopentadienes groups was prepared and characterized. The cyclopentactienes groups performed a Diels-Alder reaction to form the reversible crosslinking of the support. In olefin polymerization the crosslinked active species transformed noncrosslinked active species via MAO. The influence of the reversibility of network on olefin polymerization was investigated. The polystyrene-supported metallocene catalyst showed high activity and stable polymerization process in olefin polymerization. (c) 2005 Wiley Periodicals, Inc.