Magnetorheological　(MR)　fluid　damper　is　a　high　quality　semi-active　vibration　damping　device　based　on　magnetorheological　effect.　However,　one　of　the　key　factors　restricting　its　development　and　application　is　the　sedimentation　of　magnetic　particles　in　MR　fluids　at　present,　which　affects　the　working　stability　and　service　life　of　the　damper,　while　there　is　a　lack　of　effective　method　for　monitoring　sedimentation　state　of　MR　fluid　inside　the　device　in　real　time.　A　new　structure　of　MR　fluid　damper　for　improving　and　monitoring　the　sedimentation　stability　of　MR　fluid　is　developed　in　this　study　based　on　the　sedimentation　principle　and　work　characteristics　of　MR　damper.　Firstly,　the　theoretical　analysis　of　the　new　MR　fluid　damper　is　carried　out,　then　the　prototype　is　designed　and　processed,　the　appropriate　MR　fluid　is　selected,　finally　the　performance　of　the　prototype　is　tested.　The　results　of　experiment　show　that　the　force　of　the　new　damper　can　be　adjusted　in　both　directions,　and　the　output　force　can　meet　the　requirements　of　working　conditions.　The　resistance　of　MR　fluid　decreases　and　the　conductivity　of　MR　fluid　increases　in　the　middle　of　the　damping　channel,　and　the　partial　voltage　at　both　ends　of　the　non-inductive　resistance　increases　gradually,　which　verifies　the　feasibility　of　the　monitoring　device　for　sedimentation.　The　voltage　at　both　ends　of　the　non-inductive　resistance　decreases　slightly　after　placement　for　24　weeks,　so　it　can　be　judged　that　the　sedimentation　of　MR　fluid　is　weak　in　the　new　MR　damper,　which　verifies　the　effectiveness　of　the　new　structure　for　improving　sedimentation　stability.