Abstract: The InSAR interferogram of coal mine subsidence area is usually characterized by dense fringes，large noise and many residuals. The phase unwrapping method based on quality map is relatively stable when unwrapping the phase of this kind of interferogram. However， different quality indexes tend to focus on temporal correlation or spatial correlation unilaterally， which often leads to unsatisfied unwrapping results. In this paper，a new quality index combining phase derivative variation and correlation coefficient is proposed， which not only considers the temporal coherence between pixels， but also takes into account their spatial similarity. It is more suitable for phase unwrapping of InSAR in mine subsidence area. A set of simulated interferometric phase unwrapping results indicates that the new quality index can improve the unwrapping accuracy and avoid large error accumulation compared with phase derivative variation and correlation coefficient index. The unwrapping results of a set of real mine subsidence interferograms with complex ground cover and high noise show that the new quality index is reliable， which can effectively avoid the low unwrapping accuracy caused by the accumulation of high-quality regional errors.

Key words: mining subsidence, phase derivative variation, correlation coefficient, subsidence monitoring, phase unwrapping