Due　to　the　merits　of　high　rigidity　and　good　dynamics,　hybrid　machine　tools　have　been　gradually　applied　to　efficient　machining　of　thin-walled　workpiece　with　complex　geometries.　However,　the　discontinuity　of　tangential　component　of　toolpath　in　hybrid　machine　tools　may　cause　velocity　fluctuations,　leading　to　poor　surface　quality　of　workpiece.　In　this　paper,　a　novel　5-axis　hybrid　machine　tool　is　taken　as　an　example　to　demonstrate　a　smooth　toolpath　interpolation　method.　First,　an　adaptive　acceleration　and　deceleration　control　algorithm　is　presented　to　realize　the　smooth　transition　between　two　constrained　velocity　points.　Second,　a　spline　curve-based　interpolation　algorithm　is　proposed　to　realize　the　smoothness　of　the　trajectory.　Meanwhile,　a　parameter　synchronization　method　is　proposed　to　ensure　the　synchronization　of　the　interpolated　tool-axis　vector　and　the　interpolated　tool　tip.　Thirdly,　an　inverse　kinematic　analysis　is　conducted　based　on　an　inverse　position　solution　model　and　a　velocity　mapping　model.　Finally,　a　set　of　machining　tests　on　S-shape　workpiece　in　line　with　the　ISO　standard　is　carried　out　to　verify　the　effectiveness　of　the　proposed　smooth　toolpath　interpolation　method.