Ionomer　is　the　important　component　of　catalyst　layer,　the　content　affects　catalyst　layer　properties　and　cell　performance.　In　this　work,　a　three　dimensional　fuel　cell　model　having　agglomerate　is　established　to　explore　the　influence　of　constant　value　and　non-uniform　distribution　on　cell　performance.　The　results　show　that　more　ionomer　increases　cell　performance　in　ohmic　loss　region　but　reduces　the　performance　in　concentration　loss　region.　Higher　ionomer　content　significantly　improves　the　homogeneity　of　reaction　rate　distribution　along　thickness　direction.　Ionomer　content　has　a　great　effect　on　reaction　rate　around　inlet　region　having　sufficient　reactants.　The　content　decreasing　along　main　flow　direction　is　conducive　to　cell　performance　improvement　compared　with　the　results　obtained　from　the　other　two　directions.　The　content　reducing　from　under　land　to　channel　and　the　content　stepped　distribution　along　thickness　direction　all　can　improve　cell　performance.　The　influence　of　stepped　non-uniform　distribution　with　two　segments　or　three　segments　on　cell　performance　is　different.　Ionomer　distribution　corresponding　to　maximum　current　density　at　0.4　V　is　three　segments　along　main　gas　flow　direction,　the　content　is　41.461　vol%,　37.310　vol%,　33.513　vol%　from　inlet　to　outlet.　The　current　density　can　be　improved　by　0.577%.　©　2023　Elsevier　Ltd