The　existing　tunnel　seepage　analytical　solution　formula　does　not　consider　the　three-dimensional　drainage　system.　Therefore,　a　tunnel　seepage　calculation　model　with　drainage　system　is　established,　and　the　analytical　formula　of　tunnel　water　inflow　is　deduced.　In　addition,　the　analytical　solution　is　compared　with　the　degradation　formula　and　numerical　simulation　results　to　validate　the　rationality　of　the　analytical　solution,　and　further　examine　the　influence　of　geotextile　permeability,　drainage　pipe　spacing,　and　surrounding　rock　permeability　on　tunnel　water　inflow.　The　results　show　the　following:　(1)　The　blockage　of　geotextile,　the　increase　of　drainage　pipe　spacing,　and　the　decrease　of　surrounding　rock　permeability　coefficient　will　lead　to　the　decrease　of　water　inflow.　(2)　When　the　geotextile　permeability　decreases　in　the　range　of　10-4　and　10-7　m/s,　the　tunnel　water　inflow　reduces　significantly.　When　the　geotextile　permeability　is　less　than　10-7　m/s,　the　tunnel　drainage　system　is　blocked　completely　and　the　tunnel　loses　drainage　capacity.　(3)　The　most　reasonable　design　spacing　for　drainage　pipes　is　8　~　12　m.　(4)　The　smaller　the　permeability　of　surrounding　rock,　the　less　the　tunnel　water　inflow.　©　2023　Editorial　Office　of　Tunnel　Construction.　All　rights　reserved