Anaerobic　ammonia　oxidation　(anammox)　can　become　the　dominant　process　of　nitrogen　removal　in　constructed　wetland,　yet　whether　plants　that　are　signature　composition　of　wetland　play　a　significant　role　in　this　process　is　still　unknown.　Therefore,　this　study　investigated　the　influence　of　plants　(Phragmites)　on　the　anammox-driven　wetlands　by　comparing　the　differences　between　plant　group　and　non-plant　group.　The　results　indicated　that　the　proportion　range　of　anammox　process　in　nitrogen　metabolism　of　both　groups　was　estimated　to　be　45　%-63　%　according　to　the　detected　abundance　of　functional　genes,　and　there　was　a　significant　positive　relationship　between　anammox　proportion　and　total　nitrogen　removal　efficiency　(R　=　0.81,　P　＜　0.05),　which　confirmed　anammox　process　dominating　the　nitrogen　transformation　in　all　systems.　The　average　total　nitrogen　removal　efficiencies　in　the　systems　with　plants　addition　(84-85　%)　were　significantly　superior　than　those　in　the　corresponding　control　systems　(74-82　%),　respectively　(P　＜　0.05).　The　presence　of　plants　significantly　contributed　to　the　increase　in　the　anammox　proportion　of　nitrogen　metabolism　and　the　total　absolute　abundances　of　anammox　bacteria　(P　＜　0.05).　Partial　Least　Squares　Path　Analysis　Model　(PLSPM)　furtherly　revealed　that　the　estimated　weight　coefficients　of　plants　to　anammox　process　(R　=　1.24)　showed　the　larger　level　than　denitrification　process　(R　=　0.25).　Overall,　plants　played　an　enhancing　role　in　the　anammox　process　of　anammox-driven　wetlands,　rather　than　irrelevant　or　potential　inhibiting　role.　The　reason　was　mainly　related　to　the　plant　role　for　improving　biofilm　formation　by　extracellular　polymeric　substances　(EPS),　and　a　significant　positive　relationship　between　EPS　concentrations　(7-224　mu　g.g(-1))　and　anammox　bacteria　abundances　(1.63-7.66　x　10(8)　cells.g(-1))　was　found　(R　=　0.44,　P　＜　0.05).　Besides,　the　subsidiary　reasons　also　lie　in　the　minimal　role　of　plant　roots　under　higher　nitrogen　loading　and　the　appropriate　nitrogen　component　of　wastewater.