Multifunctional　flexible　devices　for　human　motion　detection　and　thermal　management　raised　great　attention　as　the　problem　of　the　aging　population　is　becoming　more　and　more　serious.　However,　it　is　still　a　challenge　to　endow　the　devices　with　excellent　stability　and　wide　application　scope.　Here　we　prepared　a　hydrophobic　and　conductive　fabric-based　strain　sensor　for　smart　fabric　via　successively　coating　with　polydopamine　(PDA),　polyaniline　(PANI),　polypyrrole　(PPy),　and　polydimethylsiloxane　(PDMS)　through　in-situ　polymerization　and　dip-coating,　which　could　be　used　for　strain　sensor　and　wearable　heater　both　in　air　and　underwater.　The　obtained　sample　exhibited　a　fast　electrical　response　in　500　ms　and　could　withstand　10,000　times　stretching-releasing　cycles,　additionally,　the　sample　exhibited　satisfactory　electro-thermal　and　photo-thermal　performances.　As　a　whole,　the　multifunctional　fabric-based　devices　with　excellent　performances　show　great　potential　to　be　applied　in　medical　monitoring　and　personal　care,　especially　for　aged　and　disabled　persons.　©　2022