The　monolayer　(ML)　and　submonolayer　Pt　on　both　terminations　of　PbTiO3(110)　polar　surface　have　been　studied　by　using　density　functional　theory　(DFT)　with　projector-augmented　wave(PAW)　potential　and　a　supercell　approach.　The　most　favored　ML　Pt　arrangements　on　PbTiO　and　O-2　terminations　are　the　hollow　site　and　the　short-bridge　site,　respectively.　By　examining　the　geometries　of　different　ML　arrangements,　we　know　that　the　dominant　impetus　for　stability　of　the　favored　adsorption　site　for　PbTiO　termination　is　the　Pt-Ti　interaction　(mainly　from　covalent　bonding),　while　that　for　O-2　termination　is　the　Pt-O　interaction　(mainly　from　ionic　bonding).　In　addition,　the　appearance　of　the　gap　electronic　states　in　the　outermost　layers　of　each　termination　indicates　that　a　channel　for　charge　transfer　between　adsorbed　layer　and　substrate　is　formed.　Moreover,　the　interface　hybridization　between　Pt　5d　and　O　2p　orbitals　is　also　observed,　especially　for　ML　Pt　on　O-2　termination.　The　stability　sequences　for　various　arrangements　of　1/2　ML　Pt　adsorption　conform　well　with　those　of　ML　Pt　adsorption,　and　the　most　stable　arrangement　is　energetically　more　favorable　than　the　corresponding　ML　coverage　in　the　view　of　adsorption　energy　maximization.　The　behavior,　i.e.　the　increase　in　adsorption　energy　with　decrease　in　coverage,　indicates　that　Pt-Pt　interactions　weaken　those　between　Pt　and　the　substrate.　Copyright　(C)　2009　John　Wiley　&　Sons,　Ltd.