The Sichuan Basin is one of the most important salt basins in China; nevertheless, whether it can produce industrial marine potash deposit or not remains a problem of much controversy. In this study, with the source of polyhalite, the forming condition, the sub-depression and the prediction of targets of potash deposits as main lines, and on the basis of microscopic identification, scanning electron microscope, strontium isotopic composition, seismic interpretation and magnetotelluric sounding, the authors systematically analyzed the potential of marine potash resources in the Lower-Triassic Formation, and made a prospecting breakthrough of marine potash exploration in eastern Sichuan Basin. The authors hold that the polyhalite existent in halite in eastern Sichuan Basin is authgenic, and the seawater was highly concentrated and had reached the critical point of the potassium and magnesium salts precipitation in the early Triassic period. Two sub-depressions exist in the Diangjiang salt basin, i.e. the Hexing and Dongjiachang, and the potash salt in the sub-depression was well preserved and subjected to be less reconstructed by later tectonic movements. The results of the seismic interpretation and magnetotelluric sounding were used to delineate the exploration target area of Shuanglong-Baohe Village, and resources of potash salt were predicted, which should be useful for drilling verification.