With　the　consideration　that　the　filter　parameters　are　of　additive　norm-bounded　variations,　based　on　LMI,　a　design　method　of　robust　H∞　filter　for　a　class　of　delta　operator-formulated　uncertain　system　is　studied　in　this　paper.　A　numerical　example　is　given　to　illustrate　the　effectiveness　and　the　feasibility　of　the　designed　procedures.　The　results　show　that　the　designed　filter　ensure　the　closed-loop　system　asymptotically　stable　and　the　H∞　norm　of　the　transfer　function　matrix　from　the　disturbance　input　to　the　estimative　state　error　is　bounded　by　the　expected　value,　even　if　the　parameters　of　the　plant　and　the　filter　are　of　uncertainties.　©　2009　Inderscience　Enterprises　Ltd.