TiO2　modified　steel　slag-based　permeable　concrete　(TSSPC)　was　prepared　with　nano-TiO2　incorporated　as　photocatalyst,　steel　slag　and　slag　powder　as　binder,　and　large　steel　slag　particle　as　aggregate.　The　effects　of　TiO2　content　on　the　compressive　strength,　water　permeability　and　NOx　degradation　performance　of　TSSPC　were　studied.　In　addition,　combined　with　microscopic　test　and　analysis　methods　such　as　XRD　and　SEM-EDX,　the　effect　mechanism　of　TiO2　on　the　mechanical　properties,　water　permeability　and　photocatalytic　performance　of　TSSPC　was　investigated,　laying　the　foundation　for　the　application　of　TiO2　in　permeable　concrete.　The　results　show　that　when　the　TiO2　content　is　low,　the　“nucleation　effect”　of　TiO2　particles　promotes　the　early　hydration　of　binder　materials.　However,　when　TiO2　content　is　high,　TiO2　particles　tend　to　agglomerate,　which　is　harmful　to　the　mechanical　properties　of　TSSPC.　In　addition,　as　the　TiO2　content　increases,　the　connected　porosity　and　water　permeability　coefficient　of　permeable　concrete　increase.　Compared　with　the　blank　control　group,　the　connected　porosity　and　water　permeability　coefficient　of　TSSPC　with　a　TiO2　content　of　5%　(mass　fraction,　the　same　below)　increase　by　4.　5　percentage　points　and　1.　34　mm·s　-　1　,　respectively.　The　NOx　degradation　efficiency　of　TSSPC　increases　as　the　TiO2　content　(0%　~　5%)　increases.　However,　due　to　the　agglomeration　phenomenon,　when　the　TiO2　content　exceeds　3%,　the　effect　of　increasing　the　TiO2　content　on　NOx　degradation　efficiency　decreases　significantly.　©　2024　Bulletin　of　the　Chinese　Ceramic　Society　Press.　All　rights　reserved.