The spoil area for wastes of underground engineering is featured with large scale, loose accumulations, high and steep slopes, and no roads. Traditional contact monitoring methods are difficult to operate, and representative points are difficult to choose to characterize the overall deformation of the slope. In this case, this paper attempts to apply the GB-InSAR system to carry out on-site monitoring and experimental research based on China's first large-scale groundwater storage and storage waste rock yard. The research results show that: (1) GB-InSAR full-field scanning can effectively solve the problem in selecting representative points on the side slope surface to present the overall deformation of the slope; (2) 4 different modes of the slope's -0.5mm equal displacement cross-sectional area are shown over time; (3) The final maximum landslide area of type B1 are 0.56 times at most of the cross-sectional area of -0.5mm equal displacement before the landslide, and type B2 are at most 0.96 times.