This paper proposed a digital FBG signal demodulation system based on Labview software, and realized the FBG strain sensor for demodulating wavelength. The data is also acquisited, processed and displayed by Labview software. It solved the problem of the high cost and huge volume of general spectrum demodulation equipment. Experimental research of strain sensoring was preceded using the system. Experimental results showed that: reflection wave spectrum line center drift and the axial stress had good linear relationship. When the stress was reached to 60 με, the corresponded FBG wavelength shift was about 1.90 nm.