We propose a combined minimum discontinuity phase unwrapping algorithm based on clusters. The wrapped phase image is tessellated into small regular blocks by the main node according to the computing resources and then sent to the idle computing nodes. During the unwrapping process of single block, the wrapped phase quality map is firstly computed and the wrapped phase image is partitioned into high and low quality areas; then the quality-guided and minimum discontinuity combined phase unwrapping algorithm is performed to get the initial unwrapped result. After the local unwrapping process is finished, the initial unwrapped result and the region partition result are sent to the main node. When all the blocked phases are unwrapped, the main node performs the minimum discontinuity optimization process on the border of different blocks and the adjacent low quality areas to get the final unwrapped result. Tests performed on the simulated and the real InSAS (interferometric synthetic aperture sonar) interferograms based on clusters confirm the validity and efficiency of the proposed algorithm.