N-cycling　processes　mediated　by　microorganisms　are　directly　linked　to　the　eutrophication　of　lakes　and　ecosystem　health.　Exploring　the　variation　and　influencing　factors　of　N-cycling-related　genes　is　of　great　significance　for　controlling　the　eutrophication　of　lakes.　However,　seasonal　dynamics　of　genomic　information　encoding　nitrogen　(N)　cycling　in　sediments　of　eutrophic　lakes　have　not　yet　been　clearly　addressed.　We　collected　sediments　in　the　Baiyangdian　(BYD)　Lake　in　four　seasons　to　explore　the　dynamic　variation　of　N-cycling　functional　genes　based　on　a　shotgun　metagenome　sequencing　approach　and　to　reveal　their　key　influencing　factors.　Our　results　showed　that　dissimilatory　nitrate　reduction　(DNRA),　assimilatory　nitrate　reduction　(ANRA),　and　denitrification　were　the　dominant　N-cycling　processes,　and　the　abundance　of　nirS　and　amoC　were　higher　than　other　functional　genes　by　at　least　one　order　of　magnitude.　Functional　genes,　such　as　nirS,　nirK　and　amoC,　generally　showed　a　consistent　decreasing　trend　from　the　warming　season　(i.e.,　spring,　summer,　fall)　to　the　cold　season　(i.e.,　winter).　Furthermore,　a　significantly　higher　abundance　of　nitrification　functional　genes　(e.g.,　amoB,　amoC　and　hao)　in　spring　and　denitrification　functional　genes　(e.g.,　nirS,　norC　and　nosZ)　in　fall　were　observed.　N-cycling　processes　in　four　seasons　were　influenced　by　different　dominant　environmental　factors.　Generally,　dissolved　organic　carbon　(DOC)　or　sediment　organic　matter　(SOM),　water　temperature　(T)　and　antibiotics　(e.g.,　Norfloxacin　and　ofloxacin)　were　significantly　correlated　with　N-cycling　processes.　The　findings　imply　that　sediment　organic　carbon　and　antibiotics　may　be　potentially　key　factors　influencing　N-cycling　processes　in　lake　ecosystems,　which　will　provide　a　reference　for　nitrogen　management　in　eutrophic　lakes.