According to the tectonic setting and evolution of study area, and the detection result done by EH – 4 in recent years, this paper reveals that there may be a lot of saline mineral deposits of gathering in the salt basin through the intercomparison of the chemical characteristics of salt spring water around Yanjing river and Yantang in Yanyuan of Sichuan province with that around the mining area in Mengyejing of Yunnan province, Concentrated seawater and the brine in Yanyuan, combining the salt diapirs tectonics in Yanjing river of YanYuan and predecessors' work. Becauce YanYuan sub-sag belongs to the edge of the tethys deep trough, the salt soluble minerals(rock salt and potassium magnesium salt, etc.) in the basin were possible migrated to the sag, potassium was formed by evaporating. Since the salt spring water and leaching brine have certain instruction significance for potash, the samples of salt spring water collected may be around the potassium magnesium salt in the deep Deep saline material source could well come from Cambrian salt rock layer.