In　this　paper,　we　investigate　the　Shilnikov　type　multi-pulse　chaotic　dynamics　for　a　rotor-active　magnetic　bearings　(AMB)　system　with　8-pole　legs　and　the　time-varying　stiffness.　The　stiffness　in　the　AMB　is　considered　as　the　time　varying　in　a　periodic　form.　The　dimensionless　equation　of　motion　for　the　rotor-AMB　system　with　the　time-varying　stiffness　in　the　horizontal　and　vertical　directions　is　a　two-degree-of-freedom　nonlinear　system　with　quadratic　and　cubic　nonlinearities　and　parametric　excitation.　The　asymptotic　perturbation　method　is　used　to　obtain　the　averaged　equations　in　the　case　of　primary　parametric　resonance　and　1/2　subharmonic　resonance.　It　is　found　from　the　numerical　results　that　there　are　the　phenomena　of　the　Shilnikov　type　multi-pulse　chaotic　motions　for　the　rotor-AMB　system.　A　new　jumping　phenomenon　is　discovered　in　the　rotor-AMB　system　with　the　time-varying　stiffness.　Copyright　©　2005　by　ASME.