Exposure　of　anisotropic　crystal　facets　allows　the　directional　transfer　of　photoexcited　electrons　(e(-))　and　holes　(h(+)),　for　spatial　charge　separation.　High-index　facets　with　a　high　density　of　low-coordinated　atoms　always　serve　as　reactive　catalytic　sites.　However,　preparation　of　multi-facets　or　high-index　facets　is　highly　challenging　for　layered　bismuth-based　photocatalysts.　Herein,　we　report　the　preparation　of　unprecedented　eighteen-faceted　BiOCl　with　{001}　top　facets　and　{102}　and　{112}　oblique　facets　via　a　hydrothermal　process.　Compared　to　the　conventional　BiOCl　square　plates　with　{001}　top　facets　and　{110}　lateral　facets,　the　eighteen-faceted　BiOCl　has　highly　enhanced　photocatalytic　activity　for　H-2　evolution　and　hydroxyl　radicals　((OH)-O-.)　production.　Theoretical　calculations　and　photodeposition　results　disclose　that　the　of　eighteen-faceted　BiOCl　has　a　well-matched　{001}/{102}/{112}　ternary　facet　junction,　which　provides　a　cascade　path　for　more　efficient　charge　flow　than　the　binary　facet　junction　in　BiOCl　square　plates.