A method for phase recovery from undersampled wrapped phase is presented. The original undersampled wrapped phase is sheared once along horizontal or vertical direction, and then along the other different direction again. The obtained phase is unwrapped by the least-square algorithm. The required and unwrapped phase is obtained after iterative summation. Both the simulating and experimental results prove the validity of the improved method. The results show that the proposed method can not only vary the shearing direction and shearing times flexibly according to the undersampled wrapped phase to achieve the best result, but also retrieve the phase with high accuracy from the undersampled wrapped phase with weak noise.