Authors propose a novel technique to reconstruct two-dimensional wave front from two difference wave fronts that are measured in shearing interferometers. Firstly, two one-dimensional wavefront estimates are computed using Fourier transform. The two-dimensional wave front distribution is then derived by use of least square fitting. The proposed method is applicable to cases in which the shear amount is larger than one sampling interval, and can alleviate the limitation on the shear amount imposed by conventional algorithm. Investigation into the influences of shear amount and noise level on reconstruction accuracy is made, and comparisons with other methods are also provided. Numeric simulations to confirm the proposed algorithm are carried out, and corresponding analyses and discussions are given. The results show that the method is relatively immune to noises and is promising in practical shearing interferomertry.