In the process of the safety text of the large infrastructure, strain is an important parameter which needs to be mainly detected. In order to measure the distribution of strain accurately, a method which is a continuous distributed fiber strain measurement sensing based on optical frequency domain reflectometry (OFDR) is presented. The method is on the basis of the principle of wavelength shifts of Rayleigh scattering and a demodulation algorithm of wavelength shift based on the movement window cross-correlation in spatial domain is used to gain the information of continuous distributed strain. The experimental results show that it can realize stable and effective stain sensing including the size and position in a range of 100 m whose sensing resolution can reach 20 cm. Compared with other sensing methods, it not only can text the strain quantificationally, gain the spatial information of the strain distribution, but also achieve a function of strain location.