Introduction:　As　the　largest　shallow　freshwater　lake　in　the　North　China　Plain,　Baiyangdian　lake　is　essential　for　maintaining　ecosystem　functioning　in　this　highly　populated　region.　Sediments　are　considered　to　record　the　impacts　of　human　activities.　Methods:　The　abundance,　diversity　and　metabolic　pathways　of　microbial　communities　in　sediments　were　studied　by　metagenomic　approach　to　reveal　patterns　and　mechanism　of　C,　N,　P　and　S　cycling　under　the　threat　of　lake　eutrophication.　Results:　Many　genera,　with　plural　genes　encoding　key　enzymes　involved　in　genes,　belonging　to　Proteobacteria　and　Actinobacteria　which　were　the　most　main　phylum　in　bacterial　community　of　Baiyangdian　sediment　were　involved　in　C,　N,　S,　P　cycling　processes,　such　as　Nocardioides　(Actinobacteria),　Thiobacillus,　Nitrosomonas,　Rhodoplanes　and　Sulfuricaulis　(Proteobacteria).For　instance,　the　abundance　of　Nocardioides　were　positively　correlated　to　TN,　EC,　SOC　and　N/P　ratio　in　pathways　of　phytase,　regulation　of　phosphate　starvation,　dissimilatory　sulfate　reduction　and　oxidation,　assimilatory　sulfate　reduction,　assimilatory　nitrate　reduction　and　reductive　tricarboxylic　acid　(rTCA)　cycle.　Many　key　genes　in　C,　N,　P,　S　cycling　were　closely　related　to　the　reductive　citrate　cycle.　A　complete　while　weaker　sulfur　cycle　between　SO42−　and　HS−　might　occur　in　Baiyangdian　lake　sediments　compared　to　C　fixation　and　N　cycling.　In　addition,　dissimilatory　nitrate　reduction　to　ammonia　was　determined　to　co-occur　with　denitrification.　Methanogenesis　was　the　main　pathway　of　methane　metabolism　and　the　reductive　citrate　cycle　was　accounted　for　the　highest　proportion　of　C　fixation　processes.　The　abundance　of　pathways　of　assimilatory　nitrate　reduction,　denitrification　and　dissimilatory　nitrate　reduction　of　nitrogen　cycling　in　sediments　with　higher　TN　content　was　higher　than　those　with　lower　TN　content.　Besides,　Nocardioides　with　plural　genes　encoding　key　enzymes　involved　in　nasAB　and　nirBD　gene　were　involved　in　these　pathways.　Discussion:　Nocardioides　involved　in　the　processes　of　assimilatory　nitrate　reduction,　denitrification　and　dissimilatory　nitrate　reduction　of　nitrogen　cycling　may　have　important　effects　on　nitrogen　transformation.　Copyright　©　2023　Kuang,　Xiao,　Hu,　Wang,　Zhang,　Wei,　Bai,　Zhang,　Acuña,　Jorquera　and　Pan.