The reservoir characteristics and major controlling factors of reservoir quality of the Paleogene in the southern Tarim basin are analyzed by means of massive drilling data，well logging and test data.This study shows that the reservoir of the Paleogene in the study area shows high compositional maturity and middle textural maturity，which has the characteristics that the main lithologies of the reservoir are feldspar quartz sandstone and lithic arkose，the high matrix contents and medium roundness and sorting.Types of pores of the sandstone reservoir are mainly intergranular pores，dissolved pores between grains，intragranular dissolved pores，all kinds of microporous and cracks and so on.Denudation pore is the major type，and then intergranular pore.The reservoirs are extra low porosity and permeability with the porosity ranging from 4.5% to 17.5% and permeability ranging from 0.1×10-3 μm2 to 10×10-3 μm2.The reservoir in research area is mainly affected by combined factors of depositional environment and diagenesis.The main diagenesis types are cementation and dissolution.By comprehensive analysis，the result shows that the favorable reservoir is mainly distributed in sheet sand and underwater distributary channel.