Hydrocarbon breakthroughs have been made in the Paleogene clastic rocks of Wells Chai 10 and Atan 1 in the Altun piedmont of Qaidam Basin. It is necessary to conduct fine characterization of sedimentary sand bodies and study reservoir characteristics to expand the exploration and find new exploration zones. The heavy mineral，core，thin section，and physical property，logging，and seismic data，were employed to redefine sedimentary provenances and study the types and distribution of sand bodies and reservoir characteristics. In this way，the favorable exploration zones were proposed for subsequent work. The results show that there are eight provenances in the Altun piedmont，and the boundary and distribution of the eight provenances are carefully delineated. The clastic rocks and carbonate rocks are developed in the study area，where the clastic rocks include conglomerates，glutenites，pebbly sandstones，and sandstones，demonstrating alluvial fan facies，fan-delta facies，subaqueous fan facies，and shore-shallow lake beach bar microfacies. Reservoirs are classified as medium-poor，and the argillaceous matrix content is at the level of medium-high.Controlled by the sedimentary facies zone，the physical properties of reservoirs in the alluvial fan facies and fan-delta plain subfacies are poor，and those of reservoirs in fan-delta front sub-facies and subaqueous fan facies are good while those of reservoirs from the piedmont to the basin show the characteristic of“poor-good-poor”. Hydrocarbons migrate from the hydrocarbon generation center to the piedmont and tend to accumulate in the high-quality reservoirs of fan-delta front subfacies and subaqueous fan facies as they are blocked by the tight reservoirs of alluvial fan facies and fan-delta plain subfacies in the high structural position. It is concluded that the distribution areas of fan-delta front subfacies and subaqueous fan facies are the favorable zones for future oil and gas exploration. Accordingly，the risk well Atan 2 and the exploration well Hongbei 2 are deployed.