The Mengyejing potash deposit, which is located in the southern Simao basin of eastern Tethyan realm and approximately 500 km north of the Khorat basin, is only pre-Quaternarya solid potash deposit in China. The Khorat basin contains immense potash deposits occurring mainly in the Maha Sarakham Formation. There has long been dispute about resources amounts and genesis between the Mengyejing potash deposit and the Khorat huge potash basin, especially about the questions below. Controversies still occur over potashforming ages over the late Cretaceous, Paleocene and even Jurassic; potash material sources from continental, marine and multiple sources; and their ore-formation mechanisms. Through summarizing previous research and the results in this study, we suggest that the Mengyejing Formation stratum is Albian to Cenomanian of the Late Cretaceous in age and the primary potash deposited at the same time. The primary potash was affected by multiple hydrothermal fluids during the post depositional stage, especially since 14 Ma, resulting in the formation of secondary vein-type potash. The ore-forming material of potash deposit might be dominantly sea water due to incursion of the Mid-Tethyan Ocean with minor amount of continental water and deep fluids. It can be concluded that the Simao and Khorat basins were isolated lakes in arid desert environment during the Late Cretaceous and the transgression of MidTethys Ocean from west to east resulted in flowing of seawater into Khorat basin, forming a unified Simao-Khorat Sea. This model can interpret the relation between the sources of the potash deposits and genetic link between of Simao and Khorat basins. The formation and latestage alteration of the potash deposits in the Simao basin had been controlled mainly by tectonic activities from initial faulted subsidence to compression and strike-slip by the collision of India and Asia at the post-sedimentation stage.