Based mainly on gravity data,the present paper deals with spatial distribu tion regularity of brine potash deposits in Qaidam Basin, and makes a predic tion on total potassium chloride reserves in potassium-bearing brine of this ba sin.The potash deposits in Qaidam Basin are mainly brine potash ones, which are strictly confined to the Quaternary depressions and coincide with negative gravity anomalies. The formation and development of the Quaternary depressions are in turn related intimately to the basement properties of the Qaidam massif.It is inferred from the gravity and magnetic anomalies that Qaidam Basin might be divided into eastern part and western part, and from west to east po tash deposits become younger in age and the salt layers get thinner in thick ness.The thickness of the potassium-bearing brine layer shows linear positive coorrelation with intensity of the gravity negative anomaly. On such a basis, we have made a prediction on total potash salt reserves for an area of 50000km² in the west of Qaidam Basin.