In　this　study,　two　typical　carrier　types,　microporous　and　macroporous　carriers,　were　collected　from　a　full-scale　partial　nitritation/anammox　reactor　for　analysis　and　comparison　of　the　biofilm　structure　characteristics,　performance　and　removal　nitrogen　pathway.　For　microporous　carriers,　a　thicker　biofilm　(＞5 mm)　was　obtained　with　higher　biomass　and　abundance　of　anammox　bacteria　as　well　as　a　higher　nitrogen　removal　efficiency　due　to　the　integration　of　denitrifying　and　anammox　bacteria.　In　addition,　higher　microbial　community　stability　can　be　expected　under　varying　environmental　conditions.　In　comparison,　macroporous　carrier　biofilm　exhibited　a　lower　thickness　(0.4-2.3 mm)　and　lower　microbial　richness,　with　a　strong　network　correlation　among　genera.　Analysis　showed　that　the　mainly　positive　correlation　between　anammox　bacteria　and　ammonium　oxidizing　bacteria,　enhancing　coupling　partial　nitritation　and　anammox.　These　findings　help　further　our　understanding　of　the　mechanisms　of　anammox　biofilm　nitrogen　removal　and　provide　a　baseline　for　optimization　of　the　design　of　carrier　structures.