Through　the　variable　substitution　and　separated　variable　methods,　this　study　develops　a　two-dimensional　(2-D)　axisymmetric　diffusion　analytical　solution　for　organic　pollutants　in　a　circular-shaped　cutoff　wall　(CCW)　system　for　the　first　time,　which　can　more　precisely　and　reasonably　simulate　the　diffusion　behaviors　in　＇circular-shaped＇　vertical　barriers.　Then,　the　proposed　analytical　solution＇s　reasonableness　is　verified　by　comparing　it　with　an　existing　analytical　solution　and　a　corresponding　finite-difference　solution.　Meanwhile,　the　comparison　suggests　that　this　solution　will　degrade　to　a　2-D　diffusion　analytical　solution　when　the　pollution　source　radius　is　large　enough.　Furthermore,　the　presented　analytical　solution　can　also　be　simplified　to　a　one-dimensional　axisymmetric　diffusion　analytical　solution,　or　to　the　axisymmetric　diffusion　analytical　solutions　in　a　single-layered　medium.　These　exact　analytical　solutions　can　not　only　be　applied　to　study　axisymmetric　diffusion　behaviors　under　specific　scenarios,　but　also　be　used　to　validate　other　complex　numerical　models.　Last,　a　case　study　is　conducted　to　investigate　the　impacts　of　pollution　source　concentration　distribution,　CCW　horizontal　thickness,　and　defined　equivalent　diffusion　coefficient　on　the　barrier　performance.　Overall,　the　proposed　analytical　solutions　and　obtained　diffusion　laws　in　this　study　can　provide　guidance　for　the　service　effect　assessment　and　the　engineering　design　of　cutoff　walls.　©　2024　John　Wiley　&　Sons　Ltd.