Abstract: Exploration has proved that the Enping Formation is the major hydrocarbon source rock in the Baiyun Sag, Pearl River Mouth Basin. A clear picture of its provenance is critical for petroleum geological study of this area. 3D seismic interpretation and drilling data indicate that the sediments of Enping Formation sourced not only from the northern provenance outside the basin, but also from the Southern Uplift inside the basin. The petrographical, paleo-geomorphological, seismic data and clastic zircon age from drilling wells suggest that the Enping Formation is characterized by high sandstone/formation ratio, which is over 80%, coarser grains, large-scale, high-angle, "S"-shaped and NE prograding seismic facies, palaeo-geomorphology of channels, and Mesozoic magmatic zircon age. They are completely different from the northern source outside the basin, which has relatively gentle imbricated NW prograding seismic facies, and Precambrian-Paleozoic zircon. Final analysis shows that the delta from the Southern Uplift provides sufficient terrestrial material to the southwest of the Baiyun sag at the stage of the Enping Formation, and plays an important role in the development of high-quality marine source rocks. Meanwhile, the coarse and shallow Enping Formation sandstone in the Southern Uplift is an important potential reservoir and has important exploration significance.