Abstract：In the geological evolution of the Tarim basin, many transgressions and regressions happened, which brought plenty of salt-forming materials. Furthermore, because the climate was extremely arid, abundant halite was deposited. So it is possible to find potash in the Tarim basin. Through fieldwork, the authors have found that large amounts of halite and spring brine outcrop in the western Tarim basin. Based on a brief introduction of the geological characteristics and sedimentary facies and paleogeography of the area and chemical analysis of brine samples taken from the western Tarim basin, this paper discusses geochemical parameters and the possibility of potash formation. According to the results of brine analysis, the authors have come to the following conclusions: first, most brine has been leached from very thick halite; halite is mainly of chloride type and this type of halite has not reached the stage of potash deposition; second, the contents of Br and K show that Ohsalur (WKSL) is a place meriting attention because there have been some indications of potash deposits; finally, the Br content in the Tarim basin is generally low because of only primary deposition, which has been proved by the results of the experiment and collected data; so we cannot only depend on the Br index to judge the deposition stage of halite and it is necessary to find other potash-forming models in addition to marine potash formation.