In　this　study,　new　organic-inorganic　g-C3N4/CoAl-LDH　nanocomposites　were　prepared　and　introduced　to　fabricate　photocatalytic　cement　mortars　by　internal　mixing,　coating,　and　spraying.　The　photocatalytic　depollution　of　both　g-C3N4/CoAl-LDH　and　cement　mortars　was　assessed　by　NOx　degradation　reaction　under　UV-visible　light　irradiation.　The　study　results　suggested　that　the　degradation　efficiency　of　g-C3N4/CoAl-LDH　nanocomposites　improved　with　an　increase　in　g-C3N4　content.　The　g-C3N4/CoAl-LDH1.5　nanocomposite　displayed　the　highest　NOx　degradation　capacity,　which　was　about　1.23　and　3.21　times　that　of　pure　g-C3N4　and　CoAl-LDH,　respectively.　The　photocatalytic　cement　mortars　which　were　all　fabricated　using　different　approaches　could　effectively　degrade　the　target　pollutants　and　exhibited　significant　compatibility　between　g-C3N4/CoAl-LDH　and　cementitious　substrate.　Among　them,　the　coated　mortars　showed　strong　resistance　to　laboratory-simulated　wearing　and　abrasion　with　a　small　decrease　in　degradation　rate.