Based on the systematic analysis of coal-bearing strata information revealed by cores, drillings and seismic surveys in the northern basin of the South China Sea, using the research ideas and methods of the tectonic combined with basin evolution, drilling combined with seismic section identification and deposit combined with the peat accumulation main control factors, the tectonic characteristics and evolution law of the South China Sea basin group, the sedimentary and coal-forming characteristics of each coal basin in South China Sea during late Eocene-Miocene were analyzed, and the basic understanding of coal-forming mechanism and coal-bearing strata distribution in the South China Sea basin group were obtained.The results show that the Oligocene coal-bearing strata were mainly developed in the northern basins of the South China Sea, while the southern basins of the South China Sea were more complex, with coal-bearing strata developed in Eocene, Oligocene and Miocene.The coal-bearing strata were mainly developed in the shallow water areas in the north, west and south basins of the South China Sea, including the delta plain, fan delta plain, river flood plain, lakeside plain, lagoon-tidal flat and other environments.In the late Eocene-early Oligocene, river, lakeside, delta and fan delta deposits were generally developed in the northern and western margins basins of the South China Sea, and delta and coastal deposits were developed in the southern margins basins of the South China Sea, which were all good coal-forming sittings.Among them, the coal-forming intensity of the Oligocene was the largest.In the late Oligocene, the area affected by seawater in the South China Sea basin group was continuously expanded, and the continental basin scope was correspondingly reduced, and gradually evolved into the marine-terrestrial transition facies basin and marine facies basin, and the coal-forming intensity gradually weakened.In the Miocene, most part of the South China Sea basin group were marine sedimentary environment, and only the small deltas and fan deltas were developed at the edge of each coal basin, and the coal-forming intensity was weak. © 2020, Editorial Office of Journal of China Coal Society. All right reserved.