It is well known that clay minerals are the important factor that controls sandstone reservoir properties. This paper discussed clay mineral genesis of sandstone reservoir in Tarim and Shaanxi-Gansu-Ningxia basin. Study on the relationship of reservoir properties with content, occurrence and crystalline form of clay minerals was also carried out. The results show that the influence of clay mineral on the sandstone properties associates with sandstone maturation. The influence is significant on high maturation sandstone, and it is slight on lowmaturation sandstone. The high maturation sandstone properties degrade with the increase of clay mineral content, especially, permeability, and it is enhanced by the increase of kaolinite and fillingstate clay mineral content. The results also show the influence of three  illinite crystalline forms on sandstone properties is different. Sheet like illinite is favourable to sandstone properties, while fibrous and hair form are not.