Abstract: The late Late Devonian—early Late Carboniferous conodont biostrata of Yajiao section was systematically examined and studied in this paper, based on measurement and collecting samples in this section. The systematic paleontology of some important conodonts was revised, through identifying the abundant conodonts materials from 17 conotont samples. Due to the vertical distribution of the conotonts, the strata of the zoning fossils were confirmed. Totally 7 conodonts zones were clarified from the upper part of Wuzhishan Formation to Baping Formation in the Yajia section, respectively: Palmatolepis gracilissigmoidalis zone from the upper part of Wuzhishan Formation; Siphonodella duplicate zone, S. crenulata zone, S. isosticha zone, Scaliognathus preaanchoralis zone, and S. anchoralis zone from the lower part of Baping Formation; Declinogaptus noduliferus noduliferus zone from the upper part of Baping Formation. The conodonts zones indicate that the age of Baping Formation is Late Devonian-early Late Carboniferous. The result achieved by the authors can supply reliable evidence for sequence stratigraphic division in different facies regions, especially for correlation in Early Carboniferous slope facies.