A　sufficient　condition　for　the　existence　of　the　robust　non-fragile　H　α　fault　detection　filter　is　presented,　based　on　linear　matrix　inequality　(LMI)　method,　while　considering　the　parameters＇　uncertainty　of　the　Delta-operator-formulated　systems,　and　the　additive　norm-bounded　variations　characteristic　of　the　fault　detection　filter.　A　numerical　simulation　is　applied　to　prove　the　effectiveness　of　the　designed　method.　The　results　show　that　when　the　robust　non-fragile　Hα　fault　detection　filter　is　designed,　it　is　necessary　to　consider　the　uncertainties　of　the　filter　parameters.　©　2011　IEEE.