For the anti-vibration in interferometry, a new simultaneous phase-shifting method based on Michelson polarization phase-shifting technique, is presented. In the corresponding set-up, a 2-dimentional grating is used. Through the grating, 4 diffracted beams of (±1,±1) orders are formed for the same diffracting efficiency. Let each beam pass one of four polarizing plates, of which polarization directions differ in turn by 45°. So four interferograms which have 90° phase-shifting interval are obtained simultaneously. By using the 4-bucket algorithm, the wavefront of the test piece is derived. The intensity disuniform and phase shift error are analyzed. A spherical system of a sort is tested by the advanced system and ZYGO interferometer repectively. The results show that the difference of root-mean-square and peak to valley in the two experiments are 0.012λ and 0.051λ respectively.