Chromium　is　a　common　heavy　metal　contaminant　that　is　widely　used　in　various　industrial　processes.　CuS-Bi2WO6/CNFs　composite　photocatalysts　with　different　CNFs(active　carbon　nanofibers)　content　were　prepared　by　solvothermal　method　to　improve　the　reduction　of　hexvalent　chromium　under　visible　light　irradiation.　The　samples　underwent　characterization　using　XRD,　SEM,　TEM,　XPS,　UV–Vis,　PL,　and　photocurrent　techniques　to　analyze　their　crystal　shape,　morphology,　structure,　elemental　composition,　surface　functional　groups,　and　optical　properties.　Additionally,　the　photocatalytic　reduction　activity　of　Cr(VI)　was　investigated.　The　findings　demonstrated　a　notably　enhanced　photocatalytic　activity　in　CuS-Bi2WO6/CNFs　composites　compared　to　CuS,　Bi2WO6,　and　CuS-Bi2WO6　individually.　In　the　presence　of　visible　light,　1%　CuS-Bi2WO6/CNFs　showed　excellent　photocatalytic　activity　for　Cr(VI)　reduction,　with　a　reduction　rate　of　98%　within　3 h.　Furthermore,　after　four　cycles,　the　1%　CuS-Bi2WO6/CNFs　composite　demonstrated　consistent　stability　and　recyclability.　Additionally,　an　active　group　capture　experiment　revealed　the　involvement　of　hydroxyl　radicals　(•OH),　photogenerated　holes　(h+),　and　superoxide　radicals　(•O2−)　in　the　reduction　of　Cr(VI)　by　CuS-Bi2WO6/CNFs,　with　•O2−　emerging　as　the　primary　active　species　in　the　system.　Based　on　these　findings,　we　investigated　the　photocatalytic　reaction　mechanism.　This　study　underscores　the　feasibility　of　preparing　CuS-Bi2WO6/CNFs　through　a　straightforward　and　manageable　solvothermal　approach,　affirming　the　promising　potential　of　CuS-Bi2WO6/CNFs　composites　in　hexavalent　chromium　treatment.　Graphical　abstract:　(Figure　presented.)　©　The　Author(s),　under　exclusive　licence　to　Springer　Nature　Switzerland　AG　2024.