This study investigates the evolution of the Miocene Guangle carbonate platform (or Triton Horst) of the northwestern South China Sea margin. The platform is located at a junction area surrounded by Yinggehai basin, Qiongdongnan basin and Zhongjiannan basin. Well and regional geophysical data allow the identification of the morphologic and stratigraphic patterns. The Guangle carbonate platform was initiated on a tectonic uplift during the Early Miocene. The early platform was limited at Mesozoic granitic basement, pre-Paleogene sediments localized tectonic uplift and was small extension at the beginning stage. While during the Middle Miocene, the carbonate buildup flourished, and grow a thrived and thick carbonate succession overlining the whole Guangle Uplift. The isolated platforms then united afterward and covered an extensive area of several tens of thousands of square kilometers. However, it terminated in the Late Miocene. What are the control factors on the initiation, growth and demise of the Guangle carbonate platform? The onset of widespread carbonate deposits largely reflected the Early Miocene transgression linked with early post-rift subsidence and the opening of the South China Sea. Stressed carbonate growth conditions on the Guangle carbonate platform probably resulted from increased inorganic nutrient input derived from the adjacent uplifted mainland, possibly enhanced by deteriorated climatic conditions promoting platform drowning. Therefore, tectonics and terrigenous input could be two main controlling factors on the development of the Guangle carbonate platforms and main evolution stages.