A　new　scheme　is　proposed　for　preparation　of　a　type　of　nonclassical　state　in　cavity　QED.　In　the　scheme,　an　atom　either　flying　through　or　trapped　within　a　cavity,　is　controlled　by　the　classical　Stark　effect;　this　makes　it　interact　alternately　with　a　(resonant)　classical　field　and　with　the　(dispersive)　cavity　field.　The　cavity　field,　which　allows　an　arbitrary　displacement　operation　during　the　process,　after　the　detection　on　the　atom,　finally　collapses　to　the　specific　superpositions　of　coherent　states,　with　their　weighting　factors　controllable.　The　scheme　is　also　applied　for　preparation　of　superpositions　of　motional　coherent　states　for　a　trapped　ion.　The　scheme　is　in　contrast　to　all　the　previous　ones,　and　thus　provides　a　new　perspective　for　quantum　state　engineering.　©　2010　Elsevier　B.V.　All　rights　reserved.