A　predator-prey　model　with　Holling　type　II　functional　response　incorporating　a　constant　prey　refuge　is　investigated.　Depending　on　a　constant　prey　refuge　m,　which　provides　a　condition　for　protecting　m　of　prey　from　predation,　we　show　the　instability　and　global　stability　properties　of　the　equilibria　and　the　existence　and　uniqueness　of　limit　cycles　for　the　model.　Two　examples　are　carried　out　to　illustrate　the　validity　of　our　results.　©　2008　Elsevier　Ltd.　All　rights　reserved.