By means of detailed study about the lithology, pore type, physical property and diagenesis of Paleogene Low Ganchaigou Formation reservoir in the north edge of Qaidam Basin, this paper confirms that Low-Ganchaigou Formation reservoir sandstones consist of arkose, lithic arkose and arkose rock fragment sandstone, and the cement is carbonates. The reservoir sandstones have low compositional maturity and medium textural maturity. The development extent of pore and the accumulation property have apparent deviation in different tectonic belts. Both the development extent of pore and the accumulation property in Mahai-Nanbaxiang area are best, and produced mainly primary intergranular pores. The reservoir has high porosity and middle permeability. The development extent of pore is very good to good and the accumulation property is good in Lenghu tectonic belt, and produced mainly primary intergranular pores. The reservoir has mid-low porosity and mid\|ow permeability. Reservoir porosity and accumulation property are relatively very poor in Eboliang tectonic belt, and merely has a few relict intergranular pores and secondary solution pores, and the reservoir has extremely low porosity and extremely low permeability. The rock component of sandstone reservoir and diagenesis are the main factors which control the reservoir property of Paleogene in the north edge of Qaidam Basin. The diagenesis mainly contains compaction and cementation. Carbonate cementation and clay encrustation have constructive and devastating effects to reservoir property.