with　the　development　of　flexible　electronic　technology,　sensors　are　widely　applied　in　wearable　and　implanted　electronic　devices　such　as　electronic　skin.　As　a　basic　component,　pressure　sensors　with　high　sensitivity　and　flexibility　have　received　enormous　attention.　Capacitive　pressure　sensors　are　the　most　popular　type　of　pressure　sensors　so　far　because　of　the　easy　construction　method　and　low　power　requirement.　And　how　to　enhance　the　sensitivity　and　repeatability　is　key　to　the　wide　application　of　the　capacitor-based　pressure　sensors.　Here,　we　demonstrate　an　easy　and　low　cost　method　to　achieve　a　dielectric　layer　with　sensitivity　increased　to　nearly　20　times　compared　with　pure　elastomer-based　dielectric　layer.　We　combine　a　silicone　elastomer　with　expandable　microspheres,　which　will　expand　to　nearly　four　times　when　heated.　Therefore,　the　silicone/expandable　microsphere　composites　have　a　large　amount　of　ordered　＂air　bubbles＂,　similar　to　a　foam　structure.　The　generated　dielectric　layer　we　get　after　curing　has　lower　modulus　of　elasticity　and　thus　higher　sensitivity　after　being　compressed.　Moreover,　this　composite　can　be　used　as　pressure　sensitive　coatings.　Compared　to　traditional　pressure　sensor　based　on　thin　films,　the　coating　can　be　applied　to　large　surface　areas　and　surfaces　with　various　geometries.