Abstract: Rilonggou-Saishitang region in Xinghai county,Qinghai province,lies in the north of Buqingshan-Animaqing ocean and is connected to the middle region of Hercynian Kuhai-Saishitang branch ocean through the NNE spreading.In the expansion,subduction and closure stage of the branch oceanic basin,a series of NNW and NEE distribution,main tectonic faults were formed.The effects of the geological structures spread to the development of a series of sedimentary basin and the distribution in the branch oceanic basin controling the formation and distribution of the Early Permian volcanic-formation sedimentary deposits.The existence and distribution characteristics of the above geological structure were confirmed by the acidity intrusive rock out put from the Indo-Chinese time fragile geological structure.It provids further inspiration for the sTructural framework and geological research in this area.