Abstract: According to the EW tension anomaly of the extensometer in Yixian Seismic Station on March 8, 2019, we survey and analyze the cavern environment, instrument system, power supply system and environmental disturbance, and so on. Using the systhetic aperture radar data (Sentinel-1A) which has the penetration ability to the earth surface and the remote sensing data (Landsat-8 OLI) which has abounding spectrum information, we obtain the ground environment changes around the station, found the spatial distribution of interference sources, quantitatively analyze the effect of load influences including quarry and soil excavating on the observation of the extensometer by means of artificial interpretation and statistical analysis and technology of differential interferometric synthetic radar. The result shows that the anomaly is caused by environmental disturbance.