Based on 8 wells(e.g. Zhenjia 1 well, etc) in the Northern Shaanxi salt basin, cores observation and well logging interpretation, identification of microscopic flakes, combined with regional tectonic data and previons research achievements, the Ordovician majiagou Formation rock types, sedimentary facies and sequence stratigraphy were studied. The rock types are mainly carbonates and evaporites, clastic rock and other sedimentary rocks less development.The main development of carbonate platform facies can be further divided into two subfacies: open platform and restricted evaporate platform. Open platform can identify limemud mound microfacie and the microfacies contain dolomitic flat, salt lake, gypsum lake. Sedimentary evolution shows that the salt basins in northern Shaanxi had experienced three timestransgressive regressive cycles from Ma1 to Ma6 period. Sedimentary evolution created good salt palaeogeographic environment for Shaanxi salt basin and sylvite forming,and the sea water supplied enough potassium material in the transgression. Inheritance of salt basins formed in the regressive period around the uplift at favorable evaporation low latitudes drought climate environment are was very favorable for the formation of potassium rock. Shaanxi salt basin showed the tectonic pattern of “two depressions and one lifting”, for west salt sags,middle uplift,east salt sags which are NNE striking from west to east. west salt sags are made of “west 1 salt sags”, “west 2 salt sags” and “west 3 salt sags” from north to south; East salt sags were made of”east 1 salt sage” in the north and ”east 2 salt sage” in the south.The five salt sags with the thicknesses of more than 150 meters in this region are the best locations for potassium salt formation in Shaanxi salt basin, suggestion a priority targets for potash exploratory well deployment in the favorable area.