Polydimethylsiloxanes　(PDMS)　foam　as　one　of　next-generation　polymer　foam　materials　shows　poor　surface　adhesion　and　limited　functionality,　which　greatly　restricts　its　potential　applications.　Fabrication　of　advanced　PDMS　foam　materials　with　multiple　functionalities　remains　a　critical　challenge.　In　this　study,　unprecedented　self-adhesive　PDMS　foam　materials　are　reported　with　worm-like　rough　structure　and　reactive　groups　for　fabricating　multifunctional　PDMS　foam　nanocomposites　decorated　with　MXene/cellulose　nanofiber　(MXene/CNF)　interconnected　network　by　a　facile　silicone　foaming　and　dip-coating　strategy　followed　by　silane　surface　modification.　Interestingly,　such　self-adhesive　PDMS　foam　produces　strong　interfacial　adhesion　with　the　hybrid　MXene/CNF　nano-coatings.　Consequently,　the　optimized　PDMS　foam　nanocomposites　have　excellent　surface　super-hydrophobicity　(water　contact　angle　of　≈159o),　tunable　electrical　conductivity　(from　10−8　to　10 S m−1),　stable　compressive　cyclic　reliability　in　both　wide-temperature　range　(from　−20　to　200 oC)　and　complex　environments　(acid,　sodium,　and　alkali　conditions),　outstanding　flame　resistance　(LOI　value　of　＞27%　and　low　smoke　production　rate),　good　thermal　insulating　performance　and　reliable　strain　sensing　in　various　stress　modes　and　complex　environmental　conditions.　It　provides　a　new　route　for　the　rational　design　and　development　of　advanced　PDMS　foam　nanocomposites　with　versatile　multifunctionalities　for　various　promising　applications　such　as　intelligent　healthcare　monitoring　and　fire-safe　thermal　insulation.　©　2023　Wiley-VCH　GmbH.