Gastric cancer is a highly prevalent malignancy worldwide and remains associated with poor prognosis, highlighting the urgent need for effective and low-toxicity therapeutic strategies. Akebia quinata, a plant widely used in traditional medicine, contains diverse bioactive compounds, yet its anti-gastric cancer activity and molecular basis remain poorly understood. In this work, the inhibitory activity of ethanol extracts of A. quinata obtained from different plant organs (leaves, stems, and roots) and seasons (summer and autumn) was tested in the human gastric cancer cell line MKN74 using an MTT assay, revealing that the summer root extract exhibited the strongest anti-proliferative activity (76.46% inhibition). Comprehensive chemical profiling using GC–MS and UPLC–QTOF–MS identified multiple compounds with potential anti-cancer activity, including dihydrocucurbitacin F and anemoside A3. To further investigate the potential mechanisms, network pharmacology analysis was conducted to construct a component–target–disease network, identifying AKT1 and STAT3 as key putative targets; molecular docking also suggested stable compound–protein interactions with the corresponding targets, with predicted binding free energies below −5.0 kcal/mol. Overall, these findings indicate that A. quinata root extract exerts notable in vitro anti-gastric cancer activity and may act through multi-target modulation of cancer-related signaling pathways, providing a basis for further investigation of this plant as a potential source of anti cancer compounds.