A　new　nanocomposite　g-C3N4/CoAl-LDH　was　synthesized　and　implemented　to　make　alkali-activated　steel　slagbased　photocatalytic　pervious　concrete　(ASSPPC).　The　water　permeability,　compressive　strength,　microstructure,　and　NOx　degradation　ability　of　ASSPPC　were　investigated.　The　results　show　that　at　lower　dosages　(1　wt%　and　3　wt%),　the　spherical　structure　facilitates　excellent　dispersion　of　g-C3N4/CoAl-LDH　within　the　matrix,　which　leads　to　reduced　matrix　porosity,　resulting　in　improved　compressive　strength　and　reduced　water　permeability　in　ASSPPC.　Compared　to　control　previous　concrete,　the　compressive　strength　of　ASSPPC　with　1　wt%　g-C3N4/CoAl-　LDH　increased　by　6.3%,　and　water　permeability　of　which　decreased　by　15.4%,　respectively.　However,　at　higher　dosages　(5　wt%),　g-C3N4/CoAl-LDH　tends　to　agglomerate,　causing　lower　hydration　degree　and　higher　matrix　porosity.　Moreover,　owing　to　the　remarkable　alkali　resistance　of　g-C3N4/CoAl-LDH,　ASSPPC　with　this　photocatalyst　only　marginally　decreases　its　NOx　degradation　ability　as　the　curing　age　increases.　When　considering　water　permeability,　compressive　strength,　and　NOx　degradation　ability,　ASSPPC　with　3　wt%　g-C3N4/CoAl-LDH　demonstrates　optimal　performance,　which　gives　both　compressive　strength　and　water　permeability　equivalent　to　pervious　concrete　without　photocatalyst　while　exhibiting　a　NOx　degradation　rate　0.58　times　higher　than　that　of　ASSPPC　with　3　wt%　g-C3N4.