Generalized　Feistel　networks　are　important　components　of　symmetric　ciphers,　and　detailed　security　evaluations　in　the　quantum　setting　remain　to　be　explored.　In　this　paper,　based　on　the　strong–weak　separability　of　certain　branch　output　function,　we　present　polynomial-time　quantum　distinguishers　for　4F-function　and　2F-function　structures　in　quantum　chosen-plaintext　attack　setting　for　the　first　time,　and　then　quantum　key-recovery　attacks　are　achieved　through　Grover-meet-Simon　algorithm,　respectively.　Under　the　condition　of　the　semi-strong　separability,　firstly,　we　give　a　quantum　distinguisher　on　8-round　4F-function　structure,　from　which　we　carry　out　a　12-round　quantum　key-recovery　attack　to　guess　10n-bit　subkey,　whose　time　complexities　gain　a　factor　of　2　5n　.　When　attacking　r＞　12　rounds,　we　can　recover　4　(r-　12)　n+　10　n　-bit　subkey　in　time　24(r-12)n+10n2　.　Secondly,　we　show　a　quantum　distinguisher　on　5-round　2F-function　structure,　and　a　7-round　quantum　key-recovery　attack　is　performed　on　it,　which　can　recover　3n-bit　subkey　in　time　2　1.5n　.　When　r＞　7　,　2　(r-　7)　n+　3　n　-bit　subkey　can　be　recovered　with　time　complexities　by　a　factor　of　22(r-7)n+3n2　.　Furthermore,　based　on　the　weak　separability,　a　6-round　quantum　distinguisher　for　2F-function　structure　is　constructed,　and　an　8-round　quantum　key-recovery　attack　is　achieved,　and　the　time　complexity　is　22(r-8)n+3n2　when　r＞　8　.　The　results　show　that　the　time　complexity　of　each　attack　scheme　we　proposed　is　much　better　than　that　of　Grover’s　brute　force　search.　©　2023,　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature.