Organic matter was experimentally extracted by supercritical fiuids (CO_2 +1% isopropanol) from petroleum source rocks of different thermo-maturities at different buried depths in the same stratigraphic unit in the Dongying Basin. The results show that supercritical fluid extraction (SFE) is more effective than Soxhlet extraction (SE), with higher amounts and greater varieties of hydrocarbons and soluble organic matter becoming extractive. The supercritical CO2 extraction is therefore considered more valuable in evaluation of petroleum source rocks and oil resources, particularly those of immature types. Organic matter was experimentally extracted by supercritical fiuids (CO 2 + 1% isopropanol) from petroleum source rocks of different thermo-maturities at different buried depths in the same stratigraphic unit in the Dongying Basin. The results show that supercritical fluid extraction (SFE) is more effective than Soxhlet extraction (SE), with higher amounts and greater varieties of hydrocarbons and soluble organic matters becoming extractive. The supercritical CO2 extraction is therefore more valuable in evaluation of petroleum source rocks and oil resources, particularly those of immature types.