To　investigate　methods　for　improving　the　simultaneous　partial　nitrification-anammox　and　denitrification　(SNAD)　process　for　landfill　leachate　treatment,　this　study　prepared　a　biochar/nano　zerovalent　iron　modified　polyurethane　biocarrier　(BZPU),　which　was　confirmed　to　have　excellent　nitrogen　adsorption　capacity.　The　BZPUfilled　carrier　biospheres　were　used　as　carrier　filler　in　a　biological　aerated　filter　biofilm　reactor　(BAFBZPU),　operated　in　parallel　with　a　control　reactor　(BAFPU)　under　continuous　influent　conditions　for　207　days　to　treat　landfill　leachate　and　successfully　establish　the　SNAD　process.　The　BAFBZPU　achieved　a　nitrogen　removal　rate　(NRR)　of　0.76　kg　N/(m3-d)　and　a　total　nitrogen　removal　rate　(TNRE)　of　92.0　%,　which　were　7.43　%　and　4.53　%　higher　than　that　of　the　control　group,　respectively.　Additionally,　BAFBZPU　showed　faster　start-up　speed,　better　resistance　to　shock　loading,　and　a　lower　protein/polysaccharide　(PN/PS)　ratio,　further　indicating　a　superior　biofilm　structure.　The　modified　biocarrier　also　exhibited　excellent　nitrogen　adsorption　capacity,　creating　a　favorable　substrate　microenvironment.　The　introduction　of　iron　significantly　promoted　both　anammox　and　denitrification　processes,　leading　to　the　enrichment　of　related　microbial　strains　and　the　acceleration　of　nitrogen　conversion,　which　in　turn　significantly　enhanced　the　overall　SNAD　process　and　nitrogen　removal　rate.　The　rational　use　of　BZPU　as　a　biocarrier　can　enhance　the　cost-effectiveness　of　the　SNAD　process　and　provide　a　new　perspective　for　the　treatment　of　landfill　leachate.