A method of phase-shifting measurement of interferograms is proposed by the difference between two interferograms. In this method a phase-shifting interferogram is subtracted from the other one,and then the phase-shifting difference function, in which the amplitude is correlated only with the phase-shifting value, is obtained and normalized, so the phase-shifting value can be calculated by the maximum extremum of phase-shifting difference function, meanwhile two metheds including the direct search method and the average method are introduced to determine the maximum extremum of the normalized function. Experimental and analysis results show the phase-shifting value between two interferograms can be obtained when contrast function of interferogram is determined and the results are not affected by the measured phase. And as a statistical analysis for many sampling points in spatial domain is used in calculation, the high-precision phase-shifting measurement can be achieved. For another, as Fourier transform is not used in above proposed method, and it can be used in analyzing the high spatial frequency fringes, sparse parallel fringes,even arbitrary form fringes. Meanwhile the measuring precision of the proposed method is compared with that of Fourier transform method, and it is proved the measuring precision of two methods is identical.