Abstract: At the turn of Frasnian-Famennian(F-F)in Late Devonian, the environment of earth changed rapidly. As the most developed Devonian sedimentary area in South China, Guangxi has a good record of this event. Based on the study of lithic facies, sedimentary microfacies, and fossils from a series of marine carbonate rocks, siltstone and argillaceous rocks in the Dongshan section, the boundary of F-F was confirmed, and sedimentary records related to the F-F events in this area were revealed to discuss the sea level changes at the turn of F-F. It is suggest that the boundary of F-F can be restricted to the boundary between the 49 layer and 50 layer of the section. It is assumed that two adjacent stepped sea-level rise and fall occurred at the turn of F-F, which is similar to other areas in the world.