Abstract: The study area is located in the Xichuan fault polymetallic metallogenic belt in the eastern part of South Qinling orogenic belt at the junction of Henan and Shaanxi,with good metallogenic conditions.Through geological investigation and research in this area,the results show that:①the selenium content of rock is closely related to the lithology and formation age of rock,and is positively linear related to the carbon content and sulfur content of rock;②the selenium rich rock in the black rock series is formed in the continental margin in the environment of the transition zone between the ocean and the deep sea,it is consistent with the regional geotectonic background of the northern margin of Yangtze Landmass，it is a multisource genesis,which is the result of the interaction of normal anoxic deposition and hydrothermal exhalation deposition.Based on the above analysis,two prospecting target areas have been delineated,with good prospecting prospects,which is worth conducting further work.

Key words: Black rock series,Selenium rich rock,Geochemical characteristics,Cenesis analysis