Pliocene lacustrine facies sequence in the northwestern part of the Qaidam basin in Qinghai Province hosts the inland lake facies evaporite- type celestite ore deposit with the largest reserve in China. The work on this deposit has long focused only on geological exploration and exploitation. But study of the mineral source and genetic models for the Dafengshan celestite deposit is relatively poor. In this paper, we have studied the typical sections of evaporites in the north wing, shaft and south wing of the short axis double anticline. Combined with regional geological setting of the study area and characteristics of strontium isotope data from previous research, this study discussed ore- forming material source and ore genesis of the deposit using the distribution characteristics of strontium in modern river of the Qaidam basin, major element features of evaporite sections and thin section analysis. The main conclusions have been drawn as follows. ①The long- term weathering of felsic bedrock in the periphery of Qaidam basin provides the source of strontium for the formation of celestite ore deposit. ②The significant dissolution and metasomatism of Srrich carbonatic rock, which is orebearing country rock, played an important role in the secondary enrichment of celestite mineral. ③Under the structural background of high mountaindeep basin, volatile drying provides favorable conditions for the dissolution, migration and concentration of strontium in sediments.