Abstract: This paper utilizes BDS-3 GEO satellites data and employs a non-differential and non-combined model to estimate the ionospheric TEC, providing a detailed analysis of the spatial-temporal variations of the ionosphere during magnetic storm. The results indicate that the geostationary characteristics of GEO satellites enable continuous and uninterrupted refined monitoring of specific locations in the ionosphere. The study quantifies the ionospheric response characteristics through the relative ionospheric disturbance index, finding that ionospheric disturbances in low-latitude regions are more frequent and intense. This is primarily attributed to anomalies in the neutral components of the ionospheric thermosphere and the equatorial ionization anomaly region. This research provides a reference for utilizing GEO satellites to monitor the ionosphere, revealing more accurately the characteristics and patterns of spatial-temporal variations in the ionosphere.