A　scheme　is　proposed　for　the　reconstruction　of　two-mode　entangled　states　in　cavity　QED　and　ion　traps.　For　a　two-mode　field　we　show　that　the　Wigner　function　can　be　obtained　by　measuring　the　probability　of　a　two-level　atom　being　in　ground　states　after　resonant　interaction　with　two　classical　fields　and　dispersive　interaction　with　the　two-mode　cavity　field　displaced　by　resonant　sources.　For　the　two-dimensional　motion　of　a　trapped　ion　the　Wigner　function　is　obtained　by　measuring　the　probability　of　the　ion　in　its　ground　electronic　state　after　displacing　the　ion　motion　and　then　resonantly　exciting　the　ion.