In　this　manuscript,　Cs2AgBiBr6/Bi2WO6　nanocomposites　was　fabricated　via　an　ultrasonic-assisted　process.　The　activity　of　the　as-obtained　Cs2AgBiBr6/Bi2WO6　nanocomposites　for　photocatalytic　CO2　reduction　was　studied　under　visible　light.　The　as-obtained　Cs2AgBiBr6/Bi2WO6　nanocomposites　show　a　superior　activity　for　photocatalytic　CO2　reduction　to　produce　CH4　and　CO,　with　an　optimum　activity　achieved　over　0.5　Cs2AgBiBr6/Bi2WO6.　The　obvious　superior　activity　observed　over　Cs2AgBiBr6/Bi2WO6　nanocomposites　as　compared　with　bare　Cs2AgBiBr6　and　bare　Bi2WO6　as　well　as　a　mechanical　mixture　of　Cs2AgBiBr6　and　Bi2WO6　can　be　owe　to　the　fabrication　of　an　efficient　S-scheme　heterojunction,　which　accelerates　the　separation　of　the　photogenerated　charge　carriers　in　Cs2AgBiBr6　and　Bi2WO6　without　sacrificing　the　high　redox　capability　of　Cs2AgBiBr6　and　Bi2WO6.　This　work　demonstrates　that　the　coupling　of　two　photocatalytic　materials　with　staggered　band　alignment　to　form　an　S-scheme　heterojunction　is　an　effective　strategy　to　develop　efficient　photocatalytic　systems　and　also　highlights　the　promising　role　of　using　lead　free　perovskites　in　photocatalysis.　©　2022　Dalian　Institute　of　Chemical　Physics,　the　Chinese　Academy　of　Sciences