Abstract: In recent years, after long-term analysis and research, the authors found that the ionospheric TEC anomaly obtained using the iterative method to analyze the ionospheric data has a good spatial correspondence with the occurrence of medium and strong earthquakes. Some progress has been made in the medium and long term earthquake monitoring and prediction according to the summarized anomaly characteristics. In this paper, the iterative method is used to analyze and predict anomalous regions. The sliding interquartile method is used to analyze the ionospheric TEC data in the short time series before and after moderate earthquakes in the predicted region. After removing the interference factors, obvious anomalies of ionospheric TEC variation are found. The two methods are used to judge the TEC anomalies in the ionosphere before and after moderate earthquakes, so as to provide a new idea for the study of earthquake precursors.