Abstract: Abstract: Based on the sedimentary sequence characteristics of the typical sections in different facies zones in Guizhou and Guangxi, the authors recognized two obvious sea level fluctuations during the late Early Devonian period. On such a basis, the sedimentary sequences are divided into two third grade sequences（SQ1, SQ2）. The sequences （SQ1, SQ2）can be correlated regionally. In addition, the authors observed that the curve of δ13C from Lower Devonian Dale Formation in Xiangzhou of Guangxi is coincident with the curve of the regional sea level fluctuations. This study indicates that the geochemistry as well as the sequences was well controlled by the sea level changes.