Gait　event　detection　has　been　widely　implemented　in　realtime　gait　monitoring　devices,　orthoses　and　FES　system.　Certainly,　the　latency　and　the　accuracy　of　the　gait　even　detection　under　diversities　of　gait　are　crucial.　However,　due　to　the　high　detection　accuracy　usually　comes　with　high　time-delay,　it　is　somewhat　hard　to　find　a　trade-off　between　high　accuracy　and　low　latency.　Therefore,　this　paper　presents　a　real-time　algorithm　based　on　wireless　inertial　sensor　placed　on　the　shank　for　gait-even　detection.　It　combines　the　use　of　the　cycle-extremum　and　the　updating　threshold　method　to　detected　the　heel-strike　(HS),　as　the　minimum　of　the　flexion/extension　angle,　the　toe-off　(TO),　as　minimum　of　the　angular　velocity　and　the　mid-swing　(MS),　as　maximum　of　the　angular　velocity.　The　angle　and　angular　velocity　were　collected　from　2　subjects　who　imitated　the　patient　that　suffered　from　drop-foot　for　different　degrees　to　validate　the　algorithm　against　the　wireless　inertial　measurement　system.　The　results　showed　that　the　proposed　method　achieved　comparable　levels　of　accuracy　and　significant　lower　detection　delays　compared　with　other　published　methods.