By　studying　the　workpiece-edge-coupling　(WEC)　in　five-axis　ball-end　milling,　the　contact　characteristics　between　the　workpiece　and　edge　curve　are　analyzed,　and　the　chip　model　is　extracted　and　simplified.　The　edge　curve　involved　in　the　cutting　process　of　each　edge　are　calculated　at　each　time　and　a　new　instantaneous　numerical　chip　thickness　model　is　established.　Then　the　milling　forces　and　stability　lobe　diagram　(SLD)　are　calculated　in　following　cut　process　with　lead　and　tilt　angle.　The　milling　forces　and　SLD　of　lead　angle　at　15　degrees　and　tilt　angle　at　-15　degrees　are　verified　by　comparing　with　Otzurk　model　as　references,　and　it　is　found　the　SLD　of　WEC　model　can　reflect　the　unstable　points　more　properly　than　that　of　Otzurk　model.　Also　the　vibration　in　x　and　y　directions　show　a　divergence　trend,　which　proves　the　high　precision　for　the　new　algorithm　adapted　to　the　stability　prediction　of　five-axis　ball-end　milling　process.　In　addition,　the　surface　topography　is　acquired　considering　lead　and　tilt　angle　as　well　as　forced　vibration,　and　the　result　is　consistent　with　the　experiment　in　the　existing　literature.　It　is　found　that　the　milling　forces,　SLD　and　surface　topography　show　the　same　variation　trend　with　the　increase　of　lead　and　tilt　angle.　Besides,　the　stability　region　significantly　expands　and　the　surface　topography　improves　by　applying　positive　tilt　angle　other　than　the　negative.　Then,　under　the　conditions　of　positive　lead　and　tilt　angle,　increasing　lead　angle　and　decreasing　tilt　angle　reduces　the　milling　force,　expands　the　stability　region　of　SLD　and　improve　the　surface　topography.　The　optimized　tool　posture　is　acquired　by　the　coincident　analysis　of　milling　force,　SLD　and　surface　topography　under　different　lead　and　tilt　angle.