The sandstone- type uranium deposits in the northern Ordos basin are important in north China. They have the characteristics of tabular orebody, which is different from the roll orebody in the interlayer oxidation zone sandstone- type uranium deposits. The latest study shows that the kaolinite content is relatively high in the sandstone- type uranium ore belt sandstones of the central and eastern basins, indicating that the ore- bearing bed has experienced at least one period of acidic fluids closely related to mineralization. It has similar characteristics with recent ideas that the formation of tabular orebody was related to acidic fluids discharged from the compaction of overlying mudstone. In this paper, the sandstone- type uranium deposits in the northern Ordos basin are selected as an example, and the sandstone samples of different geochemical zonation of ore- bearing bed are collected for SEM, X- diffraction, and U element content analysis. The phenomenon of relatively high kaolinite content in sandstone- type uranium ore belt and reduction belt sandstone in the northern Ordos basin is considered to be related to organic acid fluid generated in the burial evolution process of the Yan’an Formation coal seam under the ore- bearing bed. Combined with the burial evolution history of ore- bearing bed, the formation of tabular orebody is divided into three stages: closed system- organic acid fluid development stage, open system- large scale mineralization stage, oil and gas large scale dispersion- superposition transformation ore- retaining stage. It is believed that the formation of tabular orebody is the result of long- term stable interaction between alkaline uranium- containing meteoric water and organic acid fluid, and occurs on the mixed contact surface of the two fluids. In addition, the overall thickness of ore- bearing sandstone is an important factor controlling orebody morphology.