Abstract: A novel wavelength detection scheme is demonstrated for measuring the wavelength of fiber grating sensors.A new cascaded structure is used in the experimental system mu ltiplex fiber grating tunable filters.The peak wavelength of sensing signal in scanning mode is analyzed.The calibration technique is adopted by the reference wavelength,which eliminates the error induced by wavelength creepage when the filters are tuned.The results show that the detection range reaches 23nm,the wave length resolution is 3.1pm,and the strain resolution is 2.56με.