Metal-organic　frameworks　(MOFs)　are　rigorously　investigated　as　promising　candidates　for　CO2　capture　and　conversion.　MOF-on-MOF　heterostructures　integrate　bolstered　charger　carrier　separation　with　the　intrinsic　advantages　of　MOF　components,　exhibiting　immense　potential　to　substantially　escalate　the　efficiency　of　photocatalytic　CO2　reduction　(CO2RR).　However,　the　structural　and　compositional　complexity　poses　significant　challenges　to　the　controllable　development　of　these　heterostructures.　Herein,　a　conventional　MOF-on-MOF　nanocomposite　is　readily　optimized　from　a　type　II　heterojunction　to　a　state-of-the-art　cascade　Z-scheme　configuration　via　the　encapsulation　of　Pt　nanoparticles　(Pt　NPs),　establishing　synergistic　MOF-MOF　and　metal-MOF　heterojunctions　with　reinforced　built-in　electric　field.　A　cascade　electron　flow　is　thus　propelled,　vigorously　separating　the　photogenerated　charge　carriers　and　profoundly　extending　their　lifetimes.　Collectively,　the　photocatalytic　activity　of　the　cascade　Z-scheme　is　drastically　promoted,　exhibiting　a　nearly　quintuple　enhancement　in　the　CO　production　rate　over　the　original　type　II　heterostructure.　Moreover,　the　anti-sintering　capacity　of　the　developed　nanocomposite　is　unveiled,　elucidating　its　simultaneously　improved　activity　and　stability.　These　findings　present　unprecedented　regulation　over　the　configuration　of　a　MOF-on-MOF　heterojunction,　substantially　enriching　the　fundamental　understanding　and　rational　design　strategies　of　composite　materials.