Core-shell　structured　molybdenum　disulfide　(MoS2)　coated　polystyrene　(PS)　microspheres　are　synthesized　with　the　help　of　hexadecyl　trimethyl　ammonium　bromide　(CTAB)　through　negative-positive　electrostatic　attraction.　The　morphology　of　the　composite　particles　is　studied　by　scanning　electron　microscopy　(SEM),　which　apparently　provides　evidence　of　MoS2-coated　PS.　The　microspheres＇　structure　and　chemical　components　are　investigated　by　X-ray　diffraction　(XRD)　and　Fourier-transform　infrared　spectroscopy,　respectively.　The　MoS2/PS　composite　particles　show　better　thermal　stability　than　PS　according　to　thermogravimetric　analysis　(TGA).　Novel　electrorheological　(ER)　fluids　based　on　the　MoS2/PS　composite　dispersed　in　silicone　oil　are　prepared　and　further　examined　by　a　rotational　rheometer　in　a　controlled　shear　rate　mode　under　various　electric　field　strengths.　The　influence　of　factors　such　as　the　electric　field　strength,　the　particle　sizes,　the　proportions　of　the　MoS2/PS　composite　and　the　functional　groups　on　the　surface　of　PS　on　ER　properties　is　investigated.　The　related　mechanism　of　these　effects　on　ER　behaviors　is　also　analyzed　in　detail,　aiming　to　find　whether　the　graphene　analogue　MoS2　is　superior　to　graphene　when　making　them　into　ER　fluids.　MoS2　has　reversible　and　tunable　electrorheological　characteristics　and　can　transform　its　phase　from　a　liquid-like　to　a　solid-like　state　when　exposed　to　an　external　electric　field.　©　2016　The　Royal　Society　of　Chemistry.