This paper is the result of mineral exploration engineering. [Objective]The potash deposit in Laos is one of the most important potash deposits in the world. To carry out studies of the sedimentary environment during the precipitation of potassium minerals is very significant for a deep understanding of the mineralization of potash deposits here. [Methods]The insoluble minerals in the potash seams, which can retain more original information than soluble salts, is an important carrier for studying the evolution of ore- forming brine. Systematic studies on insoluble minerals in borehole ZK16 from the Haixiafeng mining area of the Vientiane Basin of Laos were conducted through microscopic identification, XRD, and SEM. [Results]Analysis results show that the insoluble materials mainly include anhydrite, boracite, hilgardite, quartz, dolomite, magnesite, calcite, and muscovite, in which anhydrite and boracite are dominant minerals. The existence and distribution characteristics of authigenic quartz and clastic muscovite reveal that continental waters have affected potash deposits to different degrees during deposition. [Conclusions]Comprehensive studies show that the process of potassium salt deposition in the study area can be divided into four distinct stages: fluctuation deposition stage, shallow water deposition stage, stable deposition stage, and reworking stage.