Transdermal　delivery　of　diclofenac　sodium　(DS)　has　drawn　much　attention　for　the　advantages　of　avoiding　first-pass　metabolism,　reduced　systemic　toxicity　and　better　patient　compliance,　but　the　successful　translation　of　reported　transdermal　drug　delivery　systems　(TDDSs)　is　still　limited　by　poor　skin　permeability　and　uncontrollable　drug　release.　Herein,　we　designed　and　fabricated　a　novel　ultrasound　responsive　TDDS　by　embedding　DS-loaded　polyester　microcapsules　into　a　hydrogel　patch　based　on　four-armed　poly(ethylene　glycol).　The　rational　design　endows　the　microcapsule-embedded　hydrogel　patch　with　good　biocompatibility,　excellent　skin-adhesion　properties　and　well-controlled　ultrasound　responsive　release　behavior.　More　importantly,　by　employing　ultrasound　as　a　simultaneous　trigger　of　drug　release　and　efficient　penetration　enhancer,　the　encapsulated　drug　could　be　released　and　pass　through　the　skin　barrier　rapidly　under　ultrasound,　while　without　the　action　of　ultrasound,　a　negligible　amount　of　drug　was　released　and　penetrated　into　the　subcutaneous　tissues　in　ex　vivo　and　in　vivo　transdermal　drug　release　experiments,　indicating　that　improved　and　controllable　transdermal　delivery　of　DS　was　achieved.　Our　work　demonstrated　that　the　microcapsule-embedded　hydrogel　patch　may　be　a　promising　candidate　as　an　ultrasound　responsive　and　enhanced　TDDS　of　DS　for　treating　diseases　such　as　arthritis　and　topical　soft　tissue　injuries.　©　2019　The　Royal　Society　of　Chemistry.