A new system on demodulation of distributed fiber Bragg grating (FBG) sensor is built using blazed fiber Bragg grating (BFBG). In order to eliminate the temperature effect on strain measurement, two adjacent FBGs (one for sensing, the other for reference) with similar central wavelength and different lengths as a probe by parallel connection are utilized. Both ends of the BFBG are connected to a piezoelectric (PZT)．A saw-tooth function voltage with 10 Hz signal is supplied to the PZT. The spectrum signal from the probe can be demodulated by the main mode and the side mode of BFBG periodically offset in the same direction. The transmitted light intensity is converted to electric current by a photodiode which is processed by a computer to display the detected strain in real time. Experimental results show that it is feasible to demodulate action spectrum by BFBG with the resolution of micro-strain detection of 5 με. The cross of FBG for temperature and strain is solved. It is testified that the system is stable, reliable, and less-expensive.