In　this　paper,　cold　sintering　was　served　as　a　forming　method　to　assist　the　conventional　sintering,　which　is　so-called　cold　sintering　assisted　sintering　(CSAS)　method.　Lead-free　K0.5Na0.5NbO3　piezoelectric　ceramics　were　prepared　by　the　CSAS　method,　and　the　effects　of　the　different　procedures　on　the　sintering　behaviors　and　electrical　properties　of　KNN　ceramics　were　studied.　Compared　with　conventional　sintering　(CS),　cold　sintering　process　can　induce　potassium-rich　phase　on　the　KNN　particle　surface,　and　remarkably　increase　both　the　green　and　sintering　density　of　KNN　ceramics.　Meanwhile,　the　potassium-rich　phase　would　transform　to　K4Nb6O17　second　phase　on　the　grain　surface,　and　subsequently　suppress　the　volatilization　of　potassium　element.　The　sinterability　and　electrical　properties　were　greatly　improved,　and　KNN　piezoelectric　ceramics　with　high　performance　can　be　manufactured　in　a　wide　sintering　temperature　range　(1055　°C–1145　°C),　which　proves　that　CSAS　has　the　potential　to　be　an　excellent　sintering　technique　for　producing　KNN　based　ceramics.　©　2018　Elsevier　Ltd