Rainwater　recycling　is　a　hot　issue　in　recent　years,　but　polypropylene　(PP)　module　as　a　new　type　of　rainwater　storage　facility　has　not　received　extensive　attention.　This　study　investigated　the　impact　of　rainwater　pollution　level,　storage　time　(ST)　and　operation　mode　(alternate　replenishment　of　rainwater　and　reclaimed　water)　on　the　pollutants　removal　performance　and　bacterial　community　characteristics　of　PP　module.　Chemical　oxygen　de-mand　(COD)　removal　efficiency　increased　from　24.58%-26.52%　to　33.23%-42.23%　with　prolonged　ST.　Oper-ation　mode　changed　the　purification　performance,　but　the　COD　removal　efficiencies　in　rainwater　and　reclaimed　water　were　always　above　28%　and　42%,　respectively.　Operation　mode　exhibited　the　greatest　impact　on　bacterial　community　structure,　followed　by　rainwater　quality　and　ST.　The　bacterial　community　classification　in　biofilm　was　different　from　that　in　water,　but　Klebsiella　was　always　the　dominant　genus.　Conditionally　rare　and　abundant　taxa　(CRAT)　and　conditionally　rare　taxa　(CRT)　were　identified　as　the　hub　taxa　of　biofilm-network　and　water　-network,　respectively.　The　potential　pathogens　in　biofilm　exhibited　more　complex　interactions　with　non-pathogenic　taxa　than　those　in　water.　Klebsiella　pneumoniae　was　the　most　dominant　species　and　identified　as　the　hub　potential　pathogen　together　with　Escherichia　coli　in　both　networks.　Bacterial　communities　in　biofilm　and　water　were　significantly　correlated　with　COD　removal　efficiency.　These　results　elucidate　the　biological　function　and　risk　of　PP　module,　and　provide　a　reference　for　the　optimization　and　operation　management　of　the　rainwater　reuse　system.