Abstract: A grounding line is the boundary between inland grounded ice sheet and a floating ice shelf and an important parameter in glacier dynamics. Precise extraction of the grounding line has a great impact on the Antarctic ice sheet mass balance and mathematical modeling of glacier dynamics. In this paper, the basic principles of grounding line extraction using DInSAR are introduced. The interference of ice flow on extraction of grounding line is removed by double differential SAR interferometry(DDInSAR) and the grounding line is detected through an interpretation of the inner of dense fringes induced by ocean tide in double differential SAR interferogram images. The mapping result is verified by comparing it to the Antarctic grounding line product, demonstrating that DDInSAR is an effective technique suitable for large-scale, continuous and high-precision grounding line extraction, thus laying a foundation for grounding line extraction and understanding of the dynamic changes in polar region.