Abstract: China’s crude oil external dependence has long remained at a high level, and shale oil has become a crucial replacement resource for domestic crude oil reserve growth and production increase. Three-dimensional development is a key technological model for enhancing the degree of reserve utilization and improving development efficiency of continental shale oil. Current research predominantly focuses on development technology optimization and analysis of main controlling factors, whereas there is a lack of a quantitative benefit evaluation system for three-dimensional development of shale oil that integrates geological, development, engineering, and economic dimensions. To address this gap, a systematic analysis was made on the main controlling factors for three-dimensional development benefit of shale oil, and a benefit evaluation index system was constructed, comprising 4 primary indices, 11 secondary indices, and 19 tertiary indices, by following the integrated approach of “geology and reservoir–development–engineering–economy”. A quantitative evaluation method for the comprehensive three-dimensional development benefit of shale oil well groups was established by integrating analytic hierarchy process and fuzzy comprehensive evaluation. Case validation was conducted using five typical well groups from different subsags within the Shengli Jiyang National Shale Oil Demonstration Zone. The results demonstrated that geological and reservoir conditions were the core factor influencing three-dimensional development benefit, with a weight of 0.4088. Single-well estimated ultimate recovery (EUR), gas-oil ratio, formation pressure coefficient, brittle mineral content, and well spacing were identified as key controlling indices. The comprehensive benefit ranking of the five well groups was D > C > E > B > A. A characteristic of multi-dimensional benefit mismatches is commonly observed in three-dimensional development of shale oil in continental fault basins, where development performance depends on the synergistic matching of geological endowment, development scheme, engineering technology, and economic investment. The evaluation system developed in this study enables graded quantitative benefit evaluation for three-dimensional development of shale oil well groups, providing methodological support for shale oil development scheme optimization, pilot test benefit evaluation, and project feasibility demonstration, and also offering a reference for improving the science and technology management and decision-making system for three-dimensional development of continental shale oil in China.