Stewart　platform-based　parallel　support　bumpers　are　widely　used　to　prevent　external　shocks　from　damaging　inertial　navigation　systems.　Aiming　at　a　severe　problem　that　the　inertially　stabilized　platform　becomes　out　of　control　as　soon　as　a　specified　shock　is　posed　on　the　base　of　the　bumper　in　shock　tests,　analysis,　and　design　of　the　18-leg　Stewart　platform-based　parallel　support　bumper　are　conducted　in　this　paper.　With　the　help　of　generalized　coordinate　definition,　a　kinetic　model　of　the　parallel　support　bumper　is　established,　of　which　inertia,　stiffness,　and　damping　matrices　are　derived　based　on　kinetic　energy,　elastic　potential　energy,　and　damping　dissipation　function,　respectively.　The　stiffness　matrix　is　subsequently　calculated　in　detail;　intensive　parameter　design　of　the　18-leg　bumpers　is　carried　out　according　to　the　principle　of　stiffness　equality　and　coupled　motion　reduction,　and　the　corresponding　kinetics　is　analyzed　with　Laplacian　transformation.　Theoretical　and　simulation　results　show　that　a　half-sinusoidal　shock　with　a　magnitude　of　25　g　along　a　horizontal　axis　of　the　bumper　base　can　cause　rotational　motion　along　the　perpendicular　horizontal　axis　with　maximum　acceleration　of　2.762　x　10(3)　degrees/s(2),　velocity　of　42.3　degrees/s,　and　displacement　of　3.16　degrees,　which　would　cause　the　aforementioned　losing　control　problem　if　the　inertially　stabilized　platform　were　not　reasonably　designed.