Abstract: The Madagascar Plateau (MADP), as a product of the separation of the Gondwana continent, exhibits unique topographic and geophysical characteristics. Through the interpretation and analysis of deep reflection seismic section A-A' across the MADP region, combined with gravity and magnetic anomaly data, the geological properties, crustal structure and sedimentary stratigraphic framework of the MADP are deeply studied, and the tectonic evolution process of lithosphere extension and rupture in the southern continental margin of Madagascar is clarified. Based on gravity and seismic data analysis, the MADP can be subdivided into the thinned continental crust in the north, the oceanic-continental transition zone (OCT) in the mid, and the thickened oceanic crust in the south. After undergoing rifting at 133 Ma, the southern continental margin of Madagascar experienced extension and rupture at 120 Ma, leading to the formation of a magmatic passive continental margin. Subsequently, influenced by the Marion hotspot (90–50 Ma), the continental and oceanic crust underwent further thickening due to magmatic activity, ultimately resulting in the present-day Madagascar Passive Margin (MADP). This research enhances our understanding of the development and evolution of MADP and has significant practical implications for determining seafloor high terrain attributes in the southwest Indian Ocean.