Since there exist vibration and orientation errors, a phase shifter usually suffers from both random translational error and tilt-shift error during phase shifting in an interferometer, and it will influence the accuracy of measurement result. So the environmental stability and the performance of phase shifter are subject to rigorous requirements in high accuracy measurement. To reduce these requirements, focusing on the problem that the nonuniformity of the background intensity and modulation will affect the calculation of phase-shift plane in random and tilt phase shifting interferograms, the acquired interferograms are normalized, and phase distribution is determined with least-squares-based iterative algorithm. During iteration, the interferograms are divided into small blocks to calculate local phase shifts, and then these phase shifts are fitted to a phase-shift plane. Results of computer simulation indicate that the proposed method can eliminate the coupling effect of background intensity and modulation on the calculation of the tilt coefficients, so it can compensate tilt phase shift errors during phase shifting. Compared with other methods, the proposed method has faster convergence as well as higher accuracy. Experimental results further demonstrate the validity of this method.