We　propose　a　method　for　sensing　the　non-specific　orientation　magnetic　field　based　on　a　simple　frequency　domain　weak　measurement　system.　The　magnetic　fields　with　different　directions　and　magnitudes　induce　the　phase　differences.　It　experimentally　and　theoretically　demonstrates　the　high　sensitivity　of　the　system　to　phase　differences,　which　confirms　the　potential　of　detecting　magnetic　fields.　We　obtain　a　sensitivity　of　1.19　nm/mT　and　a　resolution　of　0.70　x　10(-3)　mT.　Further,　the　axial　and　radial　magnetic　fields　can　be　calculated　simultaneously　by　using　the　characteristics　of　the　central　wavelength　and　intensity　of　the　spectrum.　The　method　has　a　simple　set-up　and　offers　high　sensitivity,　real-time　response　to　the　magnetic　field,　suggesting　a　new　way　of　enriching　the　detection　of　the　vector　magnetic　field.