In　order　to　evaluate　the　feasibility　of　steel　slag　powder　as　filler,　the　coating　properties　of　steel　slag　and　limestone　aggregate　were　compared　by　water　boiling　test,　the　micro　morphology　differences　between　steel　slag　powder　and　mineral　powder　(limestone　powder)　were　compared　by　scanning　electron　microscope　(SEM),　and　the　high-temperature　rheological　properties　of　asphalt　mortar　with　different　ratio　of　filler　quality　to　asphalt　quality　(F/A)　and　different　substitution　rates　of　mineral　powder　(S/F)　were　studied　by　dynamic　shear　rheological　test.　The　results　show　that　the　surface　microstructure　of　steel　slag　powder　is　more　abundant　than　that　of　mineral　powder,　and　the　adhesion　of　steel　slag　to　asphalt　is　better　than　that　of　limestone.　At　the　same　temperature,　the　lower　the　ratio　of　S/F　is,　the　greater　the　rutting　factor　and　complex　modulus　will　be.　In　addition,　the　complex　modulus　and　rutting　factor　of　the　asphalt　mortar　increase　with　the　increase　of　F/A,　and　the　filler　type　and　F/A　have　a　negligible　effect　on　the　phase　angle.