A　novel　tentacle-type　polymer　stationary　phase　covalently　modified　with　branched　polyethyleneimine　(PEI)　was　developed　for　peptides　and　proteins　separations　by　open-tubular　CEC　(OT-CEC).　The　preparation　procedure　included　the　silanization　of　capillary　inner　wall,　in　situ　graft　polymerization　and　PEI　functionalization.　A　wrinkly　polymer　surface　of　multitudinous　steric　amine　groups　was　evenly　formed　on　the　capillary　inner　wall,　and　anodic　EOF　could　be　gained　within　a　wide　pH　range　of　2.57.5.　The　electroosmotic　mobility　was　examined　for　its　dependence　on　pH　as　well　as　PEI　concentrations.　Good　repeatability　was　gained　with　RSD　for　the　migration　time　of　EOF　marker　within　4.8%　and　satisfactory　chemical　stability　was　validated.　Due　to　the　existence　of　amine　groups　on　the　surface　of　tentacle-type　polymer　stationary　phase,　the　silanol　effect　that　occurs　between　the　positively　charged　biomolecules　and　the　silanols　of　the　capillary　column　was　greatly　suppressed.　Compared　with　a　monolayer-coating　capillary,　seven　enkephalin-related　peptides　were　well　resolved　on　the　PEI-bonded　column　with　high　efficiencies.　Favorable　separations　of　peptides　and　proteins　with　high　column　efficiencies　were　obtained　in　144?000189?000　and　97?000170?000　plates/m.　Branched　PEI-bonded　tentacle-type　polymer　stationary　phase　has　been　proven　to　afford　satisfactory　retention　and　resolution　of　peptides　and　proteins.