Abstract: In order to track seismic situation and analyze abnormal properties, Hebei seismic station, China Earthquake Networks Center and Zhangjiakou Earthquake Monitoring Center Station worked together to conduct a detailed site visiting. We use three kinds of three-dimensional load model to quantify the potential interference sources, which may have caused the effect. According to the model calculation result and time correlation between the interference and the occurrence of anomalies, I think that abnormal changes of the extensometer in Zhangjiakou seismostation is not caused by the interference of construction, which is more likely to be the real movement of the earth.