The occurrence of earthquakes is often accompanied by abnormal ionospheric disturbances. To explore the correlation between earthquakes and ionospheric disturbances, this paper takes the successive earthquakes of magnitude 4.9 and 5.1 in Litang County, Sichuan Province, on September 22, 2016 as an example, based on the data of the tectonic environment monitoring network in Chinese, and combined with the ionospheric tomography technology to carry out analysis. Research has found that: (1) By analyzing the observation data of the Earth's electric field and the Global Ionospheric Map (GIM) data, significant limitations exist in analyzing moderate intensity earthquake ionospheric disturbances: GIM data is significantly affected by geomagnetic activity interference and cannot effectively identify earthquake related anomalies; (2) The use of ionospheric tomography technology revealed a sustained positive anomaly in the southern ionosphere of the epicenter before the earthquake. During the earthquake, a significant high-energy region was formed inside the ionosphere, accompanied by a dynamic process of many electrons migrating to higher altitudes. Research has shown that compared to traditional observation methods, ionospheric tomography technology can more intuitively analyze the spatiotemporal evolution characteristics of ionospheric structures during earthquake occurrence, providing important technical support for the study of earthquake ionospheric disturbance mechanisms.