The　state-space　method　is　employed　to　evaluate　the　modal　parameters　of　functionally　graded,　magneto-electro-elastic,　and　multilayered　plates.　Based　on　the　assumption　that　the　properties　of　the　functionally　graded　material　are　exponential,　the　state　equation　of　structural　vibration　which　takes　the　displacement　and　stress　of　the　structure　as　state　variables　is　derived.　The　natural　frequencies　and　modal　shapes　are　calculated　based　on　the　general　solutions　of　the　state　equation　and　boundary　conditions　given　in　this　paper.　The　influence　of　the　functionally　graded　exponential　factor　on　the　elastic　displacement,　electric,　and　magnetic　fields　of　the　structure　are　discussed　by　assuming　a　sandwich　plate　model　with　different　stacking　sequences.