The　low　Fe(III)/Fe(II)　conversion　rate　seriously　hinders　the　progress　of　heterogeneous　Fenton　reactions.　In　this　work,　g-C3N4　nanosheets/schwertmannite　(CNNS/SCH)　nanocomposites　were　fabricated　by　means　of　an　in　situ　growth　strategy　to　enhance　the　interfacial　synergistic　effect　of　photo-Fenton　systems　for　chlortetracycline　(CTC)　degradation.　More　specifically,　the　photogenerated　electrons　in　g-C3N4　can　quickly　transfer　to　the　SCH　via　Fe-N　bonds　formed　at　interfaces　of　g-C3N4　and　SCH　for　viable　Fe(III)　reduction　under　visible　irradiation,　and　thus　to　promote　the　production　of　active　radicals.　Compared　with　an　individual　CNNS　or　SCH,　CNNS/SCH　nanocomposites　exhibit　superior　photo-Fenton　catalytic　activity.　In　optimized　conditions,　98.7%　degradation　efficiency　of　50　mg　L-1　CTC　and　up　to　96.6%　of　TOC　removal　have　been　achieved　in　120　min　at　an　optimized　pH.　CNNS/SCH　nanocomposites　also　display　excellent　long-term　stability　without　obvious　deactivation　in　five　consecutive　runs　of　photo-Fenton　reactions.　Quenching　experiments　and　EPR　analyses　identify　that　hydroxyl　radicals　(center　dot　OH)　and　singlet　oxygen　(1O2)　are　the　main　active　species　contributing　to　the　degradation　of　CTC.　Mechanism　of　the　photo-Fenton-like　processes　with　CNNS/SCH　nanocomposite　catalysts　has　been　tentatively　explored　based　on　various　photoelectrochemical　measurements.　It　is　concluded　that　combinational　use　of　CNNS　and　SCH　could　significantly　promote　the　separation　of　photogenerated　electron-hole　pairs,　the　interfacial　charge　transfer　and　the　Fe(III)　reduction　at　surfaces.　This　study　might　offer　a　new　insight　for　the　construction　of　highly　efficient　photo-Fenton　catalysts　to　achieve　effective　treatment　of　priority　pollutants　in　wastewater.