To　maintain　Anammox　biomass,　different　materials　were　used　as　carriers　to　immobilize　Anammox　sludge.　The　adsorptive　property,　anaerobic　ammonia　oxidation　activity,　and　stability　of　the　particles　were　evaluated.　The　results　indicated　waterborne　polyurethane　(WPU)　was　the　most　suitable　immobilizing　material.　In　a　continuous　flow　experiment,　we　further　investigated　the　resistance　to　impact　load　and　the　anaerobic　ammonia　oxidation　activity　by　increasing　the　influent　load.　It　was　found　that　for　WPU-immobilized　particles,　no　effluent　SS　or　particles　fracture　was　observed　during　the　66-day　operation,　and　the　WPU-immobilized　particles　showed　a　strong　capability　to　retain　sludge　and　good　stability　in　the　long-term.