The “Datangpo- type” manganese deposit in southeast Chongqing formed during the interglacial period between Marinoan ice age and Sturtian ice age. It is a multi- stage, polygenetic sedimentary rhodochrosite deposit formed in the graben- horst type continental margin sedimentary basin in the southeastern margin of the Yangtze block. The ore- forming period was obviously influenced by thermal events, such as tectonic activity, magmatic activity (volcanism) and “black smoke window”, and closely related to the mineralization of the rift basin caused by the Rodinia supercontinent breakup. There is a distinct coupling relationship among glacial transition, rift basin and manganese mineralization, which also presents typical features of sedimentary geochemistry. This study carried out detailed geochemical analyses on samples of Mn- bearing ores and surrounding rock samples from different mining areas and different occurrences in the study area. The geochemical diagrams indicate that oreforming material sourced from the deep area and mineralization was affected by hydrothermal fluids. In addition, the samples are enriched in As, Sb, Sr, Mo, Ag, Ba, Th, U and other hydrothermal fluid deposition markers. The average value of ΣREE in manganese ore is 159×10-6, distinctly higher that in normal deposits manganese ore (19×10-6). V/Cr, V/(V+Ni), Ce/La and lgCe/Ce* of Mnbearing ore samples indicate that manganese deposit formed in an anoxic environment and is enriched in Mo, U and other oxidation- reduction sensitive elements. The oxidationreduction condition of the manganeseforming basin controls the formation condition of manganese ore and the metallogenic process is a comprehensive result of the transformation of mineral phases in different stages of sedimentary, diagenetic and epigenetic stages. The formation of manganese ore deposit can be divided into three stages. The first stage was the enrichment of MnO2 sediments in the upper oxidation zone of the stratified sea water in the sedimentary period. The second stage was periodic short deposition process, during which MnO2 sediments were taken to the bottom of the basin by oxygenrich underflow. The third stage was the quasi syngeneticdiagenetic period, during which MnO2 is reduced to Mn2+ in an anoxic environment under the action of anaerobic bacteria or sulfate bacteria. At the same time, OH- generated increases alkalinities of seawater at the bottom and pore fluid of seabed sediments, forming primary manganese ore deposit and Mn- bearing carbonate sediments, which were further formed into manganese ore by the diagenesis.