Sm-Fe　GMFs　with　different　thickness　were　fabricated　by　ion　beam　sputtering　deposition　(IBSD)　on　polyimide　substrate.　The　deflection　of　cantilever　beam　end　and　the　amplitude-frequency　characteristic　for　the　as-deposited　film　and　the　films　after　vacuum　annealing　treatment　at　different　temperatures　were　investigated　by　magnetostrictive　measuring　instruments.　The　results　show　that　the　resonant　phenomenon　for　cantilever　beam　structure　of　Sm-Fe　GMFs　films　are　discovered　at　low　frequencies　range(0-100　Hz).　The　magnetic　sensitivity　in　low　magnetic　field　is　improved　obviously　after　vacuum　annealing　treatment　at　200°C,　the　resonance　frequency　of　the　film　is　74.1　Hz,　and　the　value　of　the　amplitude　can　reach　300　μm,　about　3　times　higher　than　that　of　the　as-deposited　film.　Sm-Fe　GMFs　show　excellent　low　frequency　characteristic,　and　the　curve　of　resonance　behaves　consistent　with　the　driving　current　curve.