Abstract: Aiming at the problem that the traditional radar differential interferometry (DInSAR) technology can not use the phase information to identify the surface activity information of large-scale subsidence area in mining area.In this paper, the time series amplitude analysis method is used to process the amplitude data of 16 sentinel-1A scenes, and the surface backscattering coefficient of mining subsidence area from May 13, 2017 to February 25, 2018 is extracted.The time series variation characteristics of surface backscattering coefficient in the process of mining activities are analyzed by establishing the analysis model of backscattering coefficient in the study area.It is found that the surface backscattering coefficient increases gradually from the outer edge of the working face to the center of the working face, and changes sharply in the central area of the working face.By comparing the relationship between the settlement rate and backscattering coefficient of the observation points of the working face trend and tendency surface characteristics, it is found that the average correlation coefficient r is greater than 0.8 in the mining subsidence process, which has a strong correlation.The experimental results show that the backscattering coefficient can be used to analyze the law of surface dynamic subsidence rate.It is an index to identify the intensity of surface activity in large-scale subsidence area.It provides a new analysis method for surface deformation in mining area and has a good application prospect.