Both the Lop Nursalt lake and the western salt lake of the Qaidam basin, which are distributed on both sides of the Altun fault belt, produce a lot of potassium- rich brine, and also produce oilfield water in the Tarim basin and the Qaidam basin. To explore the influence of Altun fault zone on salifying of salt lake, the western Qaidam basin and Lop Nur were systematically studied based on hydrochemical and isotopic characteristics of the water in oilfield and salt lake. It is found that the formation of rich brine potassium is not simply dependent on water evaporation and concentration. The hydrogen and oxygen isotopes of intercrystalline water in the Lop Nur and the Qaidam basin water and oil field can separately reach -30‰ and 75‰, which is caused by similar geochemical factors, and may be the result of upwelling of the deep source flow along the deep and large faults in the Altun fault belt.Furthermore, strontium, boron and helium isotopic values confirmed that the Lop Nur, the Qaidam brine and the oilfield water are related to deep source flow, and also indicated that Lop Nur has many more deep source characteristics.The Altun fault plays a key role in the formation of salt on both sides. In addition to the massive inflow of surface water and then evaporation, Lop Nur may directly access deep origin supply. Oilfield water in Qaidam basin is also related to the recharge of deep source flow. Most intercrystalline brine in the western of Qaidam basin can accept the recharge of oilfield water, while a few may directly accept the recharge of deep source flow.