In　present　study,　the　hysteresis　loops　and　the　magnetic　reversal　process　of　both　the　parallel　and　the　perpendicular　oriented　Nd2Fe14B/Fe65Co35/Nd2Fe14B　trilayers　with　different　soft　phase　thicknesses　were　studied　by　the　micro-magnetism　finite　element　method.　Analysis　of　magnetization　vectors＇　evolution　in　demagnetization　process　indicates　that　the　parallel　and　the　perpendicular　oriented　trilayers　exhibit　different　magnetic　reversal　behaviors.　All　the　demagnetization　curves　of　the　perpendicular　oriented　trilayers　exhibits　＂single　phase＂　behavior,　while　noticeable　kinks　presents　in　the　demagnetization　curves　of　the　parallel　oriented　trilayers　with　the　soft　phase　thickness　equal　to　or　larger　than　12　nm.　Moreover,　as　the　thickness　of　the　soft　phase　increases,　the　remanence　(Br)　of　the　parallel　and　the　perpendicular　oriented　trilayers　increases　first,　peaks　respectively　at　1.90　and　1.93　T,　respectively,　and　then　decreases　again.　On　the　other　hand,　the　coercivity　(mu　H-0(c))　of　the　parallel　and　the　perpendicular　oriented　trilayers　drops　monotonically　with　the　increase　of　soft　layers　thickness.　As　a　result,　the　optimal　maximum　energy　product　[(BH)(max)]　of　the　parallel　and　the　perpendicular　oriented　trilayers　are　630　kJ/m(3)　and　592　kJ/m(3),　respectively.　Deviation　degree　of　orientation　was　simulated　for　the　perpendicular　oriented　trilayers　with　Ls　=10　nm.　(C)　2015　Elsevier　B.V.　All　rights　reserved.