In　recent　years,　flexible　electronic　technology　has　broken　through　the　limitation　of　traditional　electronic　devices,　which　has　been　widely　applied　in　the　fields　of　electronics,　energy,　medical　care,　information　technology,　national　defense,　etc.　As　the　basic　structural　unit　of　flexible　electronic　devices,　metal　film/　compliant　substrate　systems　inevitably　suffer　from　various　deformation　in　the　practical　application,　such　as　tension,　compression,　bending　and　torsion.　Thus,　it　is　a　big　challenge　to　prepare　the　material　systems,　design　the　film/　substrate　interfaces　and　optimize　the　structures　for　maintaining　the　structural　stability　of　metal　film/　compliant　substrate　systems.　Polydimethylsiloxane　(PDMS)　is　often　used　as　the　substrate　material　for　flexible　electronics.　However,　the　PDMS　substrates　cannot　effectively　suppress　the　strain　localization　of　the　metal　films　because　of　low　elasticity　modulus　and　poor　adhesion.　The　as-deposited　metal　films　may　even　fracture,　restricting　the　development　of　flexible　electronics.　Recently,　much　effort　has　been　devoted　to　the　deformation　and　fracture　behavior　of　metal　films　on　PDMS　substrates.　Some　strategies　have　been　proposed　to　improve　the　stretchability,　including　optimizing　the　film　preparation,　enhancing　the　interface　adhesion,　and　designing　the　geometries　of　the　films　and　substrates.　For　example,the　stress　state　of　metal　films　can　be　tuned　by　changing　deposition　parameters.　A　compressive　stress　in　metal　films　is　beneficial　to　the　stretchability.　The　stretchability　can　also　be　improved　by　interfacial　adhesion　strategies,　such　as　ultraviolet-ozone　(UVO)　treatment,　oxygen　plasma　treatment,　and　adding　adhesion　interlayers.　However,　the　improvement　of　the　stretchability　is　considerably　limited　by　optimizing　film　preparation　and　enhancing　interface　adhesion.　Recent　studies　have　demonstrated　that　the　stretchability　would　be　significantly　improved　by　introducing　the　wrinkling/　buckling　structures　in　films　or　substrates,　which　provides　a　possibility　for　the　practical　application　of　flexible　electronics.　Additionally,　as　one　of　the　most　common　failure　modes　of　metal　thin　films,　cracking　will　remarkably　impair　the　stretchability,　which　usually　should　be　avoided.　On　the　contrary,　it　is　helpful　to　achieve　some　functionalities　by　controlling　the　fracture　behavior　of　the　metal　films.　For　example,　it　has　been　demonstrated　that　the　highly　sensitive　flexible　strain　sensors　can　be　developed　by　manipulating　the　cracking　behavior　of　metal　thin　films.　This　review　summarizes　the　research　progress　of　deformation　and　fracture　behavior　of　metal　films　on　PDMS　substrates,　and　introduces　the　strategies　for　improving　the　stretchability,　including　optimizing　film　preparation,　modifying　the　PDMS　surface,　adding　the　adhesion　interlayers　and　designing　wrinkling/　buckling　structures.　By　analyzing　the　current　challenges　and　future　opportunities,　this　review　is　expected　to　provide　the　theoretical　reference　for　the　preparation　of　optimization　and　structural　design　of　high-performance　flexible　electronic　devices.　©　2022　Cailiao　Daobaoshe/　Materials　Review.　All　rights　reserved.