The　digital　microfluidic　biochips　(DMFBs)　have　the　advantages　of　high　precision,　small　consumption　of　samples/reagents,　and　high　flexibility　in　experimental　places.　Nowadays,　DMFB　technology　has　been　implemented　in　industry,　such　as　by　illumina.　However,　similar　to　the　situation　faced　in　integrated　circuits,　DMFBs　also　suffer　from　various　security　risks　and　end　users　usually　know　little　about　these　security　threats.　Accordingly,　in　this　paper,　we　propose　a　survey　on　DMFBs　security　in　the　research　community.　First,　we　prevent　an　overview　of　the　attack　behaviors　in　DMFBs　and　list　them　according　to　the　design　and　manufacture　flow.　Then,　we　outline　the　current　defense　techniques　and　classify　them　into　several　categories　according　to　their　corresponding　purposes　and　functions.　Finally,　the　comparison　between　security　threats　faced　in　DMFBs　and　the　corresponding　defense　techniques　are　provided　and　analyzed　in　detail,　thus　presenting　the　future　research　trends　in　DMFBs　security.　©　2020　IEEE.