The　nonlinear　vibration　behaviors　of　stiffened　cylindrical　shells　under　electromagnetic　excitations,　transverse　excitations,　and　in-plane　excitations　are　studied　for　the　first　time　in　this　paper.　Given　the　first-order　shear　deformation　theory　and　Hamilton　principle,　the　nonlinear　partial　differential　governing　equations　of　motion　are　derived　with　considering　the　von　Karman　geometric　nonlinearity.　By　employing　the　Galerkin　discretization　procedure,　the　partial　differential　equations　are　diverted　to　a　set　of　coupled　nonlinear　ordinary　differential　equations　of　motion.　Based　on　the　case　of　1　:　2　internal　resonance　and　principal　resonance-1/2　subharmonic　parametric　resonance,　the　multiscale　method　of　perturbation　analysis　is　employed　to　precisely　acquire　the　four-dimensional　nonlinear　averaged　equations.　From　the　resonant　response　analysis　and　nonlinear　dynamic　simulation,　we　discovered　that　the　unstable　regions　of　stiffened　cylindrical　shells　can　be　narrowed　by　decreasing　the　external　excitation　or　increasing　the　magnetic　intensity,　and　their　working　frequency　range　can　be　expanded　by　reducing　the　in-plane　excitation.　Moreover,　the　different　nonlinear　dynamic　responses　of　the　stiffened　cylindrical　shell　are　acquired　by　controlling　stiffener　number,　stiffener　size,　and　aspect　ratio.　The　presented　approach　in　this　paper　can　provide　an　efficient　analytical　framework　for　nonlinear　dynamics　theories　of　stiffened　cylindrical　shells　and　will　shed　light　on　complex　structure　design　in　vibration　test　engineering.