A high precision and wide scale fiber Bragg grating (FBG) sensor interrogation system based on fiber Fabry-Perot tunable filter (FFP-TF) is demonstrated. By dynamic tracking and locking of the driving voltage of FFP-TF, the output wavelength of the laser is locked at the -3 dB reflectivity spectrum of the FBG. A temperature immune Fabry-Perot international telecommunication union filter is used as the reference channel. The interpolation algorithm is then used to realize high precision interrogation of dynamic strain. This design resolves the conflict between resolution and measurement scale in interrogation system based on optical filter. A high resolution better than 2 pm within wide strain measurement range is verified by experiments. The polynomial result of FBG spectrum is 0.998.