A method of speckle Correlation measuring is presented. It performs fractional Fourier transform instead of Fourier transform in matched filtering Correlation to obtain better recognition peak. Based on the exponential property of fractional Fourier transform, The shifting problem of fractional domain spectrum from the shift-variant property of fractional Fourier transform is solved by use of phase modulation to the specklegram,. The results of simulation and displacement fields measuring of object stretched indicate that this method is feasible, and Fractional Correlation peaks can be optimized through choosing the transform orders and phase modulation function.