It is of great significance to determining the amount of adsorbed oil and its control factors for the evaluation of shale oil resources and prediction of play fairway in shale oil exploration. The Shahejie shale in the Jiyang Depression is taken to determine the quantity of adsorbed shale oil by improved pyrolysis experiments. Meanwhile, the study reveals the factors influencing shale oil adsorption volume such as shale physical properties, shale compositions, shale oil components, as well as maturity of organic matters, temperature and pressure, etc., by an integration of molecular simulation technology, micro-adsorption mechanism and macro-experimental data. The results show that shale oil reservoirs featuring large pore volume, high TOC content, low saturated hydrocarbon content, low maturity, and low temperature, are of higher oil adsorption capacity, and TOC content and organic matter maturity are the main factors controlling oil adsorption of lacustrine shale oil reservoirs with low maturity.