Phase unwrapping is the reconstruction of a function of a grid given its values mod 2??, which is a key problem in all quantitative applications of synthetic aperture radar (SAR) interferometry and other related fields. In this paper, a path following algorithm for phase unwrapping based on priority queue and quantized quality map is proposed and tested. A discrete quality map and a priority queue are designed to accelerate the unwrapping process, which can greatly reduce the unwrapping time compared with the conventional quality-guided algorithm. The test performed on real interferometric SAR data confirms the efficiency and accuracy of the proposed algorithm.