In　this　study,　an　electrolysis-assisted　down-flow　constructed　wetland　(E-DFCW)　was　successfully　established,　and　achieved　simultaneously　efficient　removal　of　PO43−-P　(93.6%　±　3.2%),　NO3−-N　(97.1%　±　2.0%)　and　TN　(80.6%　±　5.4%).　When　compared　with　electrolysis-assisted　up-flow　constructed　wetland　(E-UFCW),　E-DFCW　allowed　significantly　lower　concentrations　of　PO43−-P,　NO3−-N,　total　Fe　and　SO42−-S　in　effluents.　In　addition,　microbial　community　and　functional　genes　prediction　results　indicated　that　hydraulic　flow　direction　significantly　altered　microbial　nitrogen,　sulfur　and　carbon　metabolisms　in　electrolysis-assisted　constructed　wetlands　(E-CWs).　Specifically,　multi-path　denitrification　facilitated　NO3−-N　reduction　in　cathodic　chamber　of　E-DFCW,　whereas　autohydrogenotrophic　denitrification　might　dominate　NO3−-N　reduction　in　cathodic　chamber　of　E-UFCW.　More　abundant　and　diverse　denitrifiers　in　cathodic　chamber　of　E-DFCW　contributed　to　enhanced　denitrification　performance.　Overall,　this　work　provides　microbial　insights　into　multi-path　nitrogen　metabolisms　in　electrolysis-assisted　denitrification　systems　in　response　to　hydraulic　flow　direction.　©　2021　Elsevier　Ltd