The　laser　from　broadband　laser　source　enters　into　the　fiber　Bragg　grating　after　drilling　through　the　coupler,　if　it　meets　the　conditions　to　specific　wavelength,　the　light　will　be　reflected　in　accordance　with　backtrack　by　Fiber　Bragg　Grating,　and　enters　into　F-P　filter.　Wavelength　selected　by　F-P　filter,　so　various　peaks　of　corresponding　wavelength　will　be　detected　by　photoelectric　detector,　F-P　filter　measures　the　wavelength　reflected　by　fiber　grating　sensor,　and　transforms　the　wavelength　signals　into　electrical　signals　directly.　Consequently,　According　to　empirical　formula　we　can　get　the　corresponding　temperature.　However,　when　the　temperature　changes,　that　the　cavity　length　of　the　F-P　filter　will　cause　excursion　and　the　measurements　of　Fiber　Bragg　Grating　Wavelength　will　cause　error　will　make　error　on　temperature.　So　before　formatting　the　system　we　should　get　the　calibration　of　measuring　system　by　accidental　devices.　That　is　to　say,　we　get　the　calibration　of　central　wavelength　of　the　FBG.　In　this　paper,　DSP　system　generates　scanning　voltage　of　the　F-P　filter　and　collects　voltage　signal.　So　we　get　the　scanning　voltage　of　transmission　peak　wavelength　of　the　F-P　filter,　thus　a　record　of　all　wavelength　-　voltage　relationship　for　the　data　can　be　obtained　by　us.　This　is　the　basis　and　standards　that　the　wavelength-voltage　data　is　used　to　demodulate　the　wavelength　of　FBG.