The　generation　of　H2O2　and　the　regeneration　rate　of　Fe2+　both　affect　the　degradation　performance　of　the　electro-Fenton　(EF)　process.　Therefore,　it　is　important　to　develop　a　cathode　that　efficiently　produces　H2O2　and　re-generates　Fe2+.　In　this　study,　graphite　felt　(GF)　was　modified　via　a　simple　hydrothermal　method　using　ammonium　persulfate　as　the　modifier.　The　physicochemical　and　electrochemical　properties　of　hydrothermally　modified　GF　(H-GF)　were　substantially　improved.　The　surface　of　H-GF　was　successfully　doped　with　O　and　N,　and　its　oxygen　reduction　reaction　activity　increased　significantly.　Compared　with　raw　GF,　the　yield　of　H2O2　and　the　regeneration　rate　of　Fe2+　of　H-GF　were　considerably　improved.　The　EF　system　constructed　with　H-GF　as　the　cathode　could　completely　remove　diuron　at-0.65　V/SCE　within　40　min.　In　the　EF　system,　H-GF　exhibited　an　excellent　degradation　effect　in　different　types　of　water　(tap　and　river　water)　and　different　pollutants　(amoxicillin,　atrazine,　and　sulfamethoxazole).　After　the　40th　cycle,　the　H-GF　cathode　retained　excellent　stability.　According　to　density　functional　theory　calculations,　H2O2　and　Fe2+　were　easily　generated　due　to　the　low　energy　barrier　required　for　the　adsorption　of　O-2　and　Fe3+　on　H-GF.　Finally,　a　possible　degradation　path　of　diuron　in　the　EF　process　was　proposed,　and　the　toxicity　of　the　intermediates　produced　in　the　degradation　process　of　diuron　was　analyzed.