Eastern Guizhou sag zone is an important manganese mineralization belt in China, where a complete set of Neoproterozoic Datangpo "black rock series" has been developed. Xixibao manganese deposit is studied in terms of petrology, mineralogy, geochemistry and other methods in this study to explore the mineral sources of the manganese deposit that hosted in "black rock series". Studies show that: the complicate mineral composition, the diverse types of ore structures, based on the study on trace elements, in addition to enrichments in As, Sb, Ag, Co, Mo, W, Cs, Ba, the ratios of Fe/Ti, (Fe+Mn)/Ti, A1/(AI+Fe+Mn), Y/Ho, Nb/Ta and the diagrams of Cr-Zr, Th-U, all show that hydrotherm contribute the process of the sedimentation. The V/(V+Ni) and V/Cr indicate an anoxic sedimentary environment for these rocks. In addition, the REE distribution patterns, Ce and Eu anomalies, La-Ce and La/Yb-EREE diagrams all suggest that the manganese deposit may have been formed in a passive continental margin with hydrothermal sedimentary affection. All the evidence above show that the manganese deposit has been formed in an ancient passive continental margin rift environment, it is the hydrothermal activities that provided the deposit with massive source material. This research may provide a new idea for the exploration of manganese deposits in Songtao County.