In the Eogene and Neogene,Qaidam Basin experienced the multiphase tectonic movement;the paleoclimate evolved from warm-humid to arid;the water in the basin was gradually salinized;the depocenter migrated from west to east.The master factors and developmental characters of lithologic hydrocarbon reservoirs have their own  particularity.Taking the fine exploration zones of the southwest hydrocarbon-rich depression in Qaidam as the key point, with the analysis of source-rock distribution,sedimentary evolution and sedimentary system distribution,the author proposes that the density difference increases after the fluvial water enters,then dam and bar sand bodies are formed easily due to density flow.Highstand system tract and transgressive system tract below the maximum flooding surface are the main exploration areas of lithologic reservoir.The Eogene slope setting sin southwest Qaidam provide the basic accumulation condition for lithologic reservoirs. The broad structures and the nose-like uplifts are favorable for lithologic reservoirs;structural settings and sand genesis determine the local accumulation of oil and gas; the broad platforms within slope settings are the main oil-gas accumulation areas of downsource and within-source lithologic reservoirs.The dam and bar sandbodies in saline lake basin, the meare dam sand bodies of the transgressive system tract,the insular sandbodies within the fan-delta and delta front,and the algal limestones widely distributed over the meare are the main exploration domains of lithologic hydrocarbon reservoirs.