Sulfur-driven　autotrophic　denitrification　(SADN)　is　a　promising　technology　for　nitrogen　removal　from　wastewater.　In　this　study,　different-strength　SMFs　(0,　5,　20,　50,　70　mT)　were　evaluated　to　investigate　the　potential　of　external　static　magnetic　field　(SMF)　for　enriching　sulfur-oxidizing　autotrophic　denitrifiers　(SOAD).　50-mT　and　70-mT　SMFs　were　most　suitable　to　accelerate　the　growth　of　SOAD　and　the　elimination　of　non-SOAD.　The　relative　abundance　of　Thiobacillus　significantly　increased　(p　＜　0.01)　from　6.26%　in　control　reactor　to　36.15%　under　50　mT　and　52.51%　under　70　mT.　Under　50　mT,　Thiobacillus　denitrificans　accumulated　most　rapidly,　with　the　largest　population.　Furthermore,　functional　gene　forecast　by　high-throughput　and　metagenomic　sequencing　indicated　that　SMF　changed　the　two-component　system,　the　adenosine　5＇-monophosphate-activated　protein　kinase　(AMPK)　signaling　system,　the　phosphotransferase　system　(PTS),　as　well　as　N/S-related　enzymes　to　regulate　stress　response　and　promote　the　growth　of　SOAD.　The　findings　indicated　that　SMF　accelerated　the　start-up　of　SADN.