The　utilization　of　halophilic　bioresources　is　limited　due　to　a　lack　of　isolation　and　characterization　work.　A　halophilic　bacterium　strain　SND-01　of　Exiguobacterium　mexicanum　was　isolated　in　this　study,　which　is　the　first　report　on　its　novel　function　in　heterotrophic　nitrification-aerobic　denitrification　(HN-AD).　The　strain　SND-01　is　slightly　halophilic,　surviving　at　0　up　to　9%　(w/v)　salinity.　When　utilizing　ammonium,　nitrate　or　nitrite　as　the　sole　nitrogen　source　in　aerobic　conditions,　the　isolated　strain　showed　the　maximum　nitrogen　removal　rate　of　2.24 ± 0.14 mg/(L·h),　3.63 ± 0.21 mg/(L·h)　and　2.30 ± 0.23 mg/(L·h),　respectively.　Functional　genes　and　key　enzymes　involved　in　heterotrophic-aerobic　nitrogen　transformations　were　characterized,　establishing　the　pathway　of　HN-AD.　The　nitrogen　removal　via　HN-AD　is　dependent　on　the　C/N　ratio,　salinity　and　temperature.　The　halophilic　Exiguobacterium　mexicanum　strain　SND-01　shows　a　significant　potential　in　biotreatment　of　saline　wastewater　in　an　easy　and　cost-effective　way.