Abstract: We propose a combined phase unwrapping algorithm using region partitioning. The wrapped phase image is partitioned into high and low quality areas according to its quality map, and a quality guided algorithm is performed to get the initial unwrapped result. A quality guided strategy is adopted to identify low quality areas, and each low quality area is stored separately. The low quality areas are optimized by a minimum discontinuity phase unwrapping algorithm one by one, and then the final unwrapped result is obtained. An unwrapping test performed on an InSAR interferogram shows that the proposed algorithm is more efficient than the minimum discontinuity phase unwrapping algorithm, and the unwrapped result was more accurate than results obatained from a quality guided algorithm.