In　urban　areas　with　many　buildings,　the　transmission　of　5　G　signals　can　be　greatly　absorbed　or　reflected,　leading　to　decreased　effectiveness　of　transmission.　To　address　the　issues　mentioned　above,　the　functional　admixture　formed　by　the　mixture　of　nanocrystalline　cellulose　(NCC)　and　diammonium　hydrogen　phosphate　(DAP)　is　added　into　concrete　in　this　study,　the　electromagnetic　transmission　performance　(ETP)　and　mechanical　properties　of　concrete　are　enhanced　simultaneously　for　the　first　time,　and　the　electromagnetic　transmission　coefficient　of　concrete　is　doubled.　When　NCC　and　DAP　are　mixed,　the　electromagnetic　transmission　coefficient　of　concrete　improved　by　117.65　%-124.35　%,　among　which,　when　0.5　wt%　DAP　and　4　wt%　NCC　are　mixed,　the　electromagnetic　transmission　coefficient　of　concrete　is　the　highest,　and　some　frequency　bands　are　as　high　as　70　%,　meeting　the　requirements　of　electromagnetic　wave　transmitting　materials.　In　addition,　the　compressive　strength　of　concrete　containing　4　wt%　NCC　and　0.5　wt%　DAP　increases　by　24.3　%　compared　to　concrete　containing　only　4　wt%　NCC.