The sedimentary manganese carbonate deposit discovered in the Meso- Neoproterozoic Wanbaogou Group in the Santonggou area, East Kunlun, Qinghai Province is an important breakthrough in manganese exploration in Qinghai Province in recent years. Five proven manganese ore bodies were documented in the mining area from bottom to top, among which No. Ⅰ- Ⅲ manganese ore bodies are located in the lower part of the Wanbaogou Group (called the lower manganese deposit), and No. Ⅳ- Ⅴ manganese ore bodies are located in the upper part (called the upper manganese deposit), with an average grade of about 15%, large thickness and wide extent, and have great exploration and development potential. Field measurements, petrology and geochemical analysis of manganese- bearing rock series were undertaken to discover the metallogenic controlling factors and genesis mechanism of mineralization. The results indicate that the manganese deposits in the Wanbaogou Group show positive Ce anomaly, developing strawberry pyrite particles with particle size greater than 6 μm, Mn/Fe value less than 6 and negative δ13C excursion. All these characteristics reflect the formation of manganese deposit: manganese was firstly precipitated and enriched as oxides or hydroxides in oxygen- rich water. In the early diagenesis stage, manganese was reduced to Mn2+ under reducing conditions with rich organic matter, and combined with CO2- 3 produced by decomposition of organic matter to form manganese carbonate. The lower manganese deposits show positive Eu and Y anomalies, with Al/(Al+Fe+Mn)＜0. 35, (Fe+Mn)/Ti＞20±5, and Fe/Ti＞20, showing hydrothermal deposition characteristics, indicating that the manganese is mainly derived from hydrothermal solutions. The SiO 2 and Al 2O 3 diagram placement of the upper manganese deposit is in the transition zone between normal deposition and hydrothermal deposition. The contents of Al 2O 3 and TiO 2 used as proxies for terrigenous input are very high and the volcanic activity is strong in the same period. The analysis suggests that both terrigenous and hydrothermal sources provide the manganese in the upper manganese deposit. 〖JP2〗According to SiO 2- K 2O/Na 2O and La/Ce- Al 2O 3/(Al 2O 3+Fe 2O 3) diagrams, combined〖JP〗 with the analysis of sedimentary facies and tectonic evolution history, it is concluded that the lower manganese deposits of the Wanbaogou Group in the Santonggou area were formed in aninitial ocean basin environment under an extensional background and the upper manganese deposits in arestricted deep shelf environment. Restricted deep shelf and basin, two manganese metallogenic models have been established in the study area.