Mahai Salt Lake is a dry salt lake rich in low-grade solid potash ore formed in the Holocene in the Qai-dam Basin,with great potential for water-soluble exploitation of potash.In this paper,the lithology of sedimentary rhythm of salt-bearing strata,the distribution characteristics of potash minerals and ore beds are studied by using the rock and mineral identification method.The results show that in the main sedimentary center of the northern mining area of the Mahai Salt Lake,a set of sedimentary strata dominated by clay,silt,rock salt,silty rock salt was deposited,while a secondary sedimentary center was formed in the southeast;The potash minerals in the study area are mainly halogenite,carnallite and potash salt;The results of sedimentary rhythm analysis show that the potash deposits are mainly distributed at the top of the Ⅳ₂ rhythmic layer and the Ⅳ₃ to Ⅳ₄ rhythmic layer,and the occurrence pattern is stratified and lenticular in the vertical direction,and is distributed in the NE-SW direction in the plane with weak continuity.The distribution of potash minerals and ore beds is closely related to the sedimentary evolution,indicating that the sedimentary characteristics have an important influence on the water solution mining of potash ore in the study area,which provides some references for the mining of the same type of low-grade potash ore.