To investigate the effects of combined treatment with a low temperature (0±1 ℃), ozone (O3) fumigation, and modified atmosphere packaging (MAP) on the postharvest quality of fresh American ginseng, experiments were conducted using 0.5×10-6 O3 fumigation for 30 min in combination with four MAP materials (IE3900-MY, IE3900-L400, IE3900-MK10, and L400 PBAT-HP101), with the polyethylene (PE) group as the control. The preservation quality was comprehensively evaluated based on multi-dimensional indexes (appearance quality, in-bag CO2 and O2 contents, water loss rate, spoilage rate, antioxidant enzyme activity, and saponin content). Treatment with O3 fumigation and L400 PBAT-HP101 packaging led to a significant delay in quality deterioration. At 120 d of storage, the water loss rate decreased by 1.19% and the decay rate decreased to 1/7 that of the PE group. Treatment with O3 fumigation and IE3900-MK10 packaging resulted in the activation of the antioxidant defense system, increasing the activities of the antioxidant enzymes PAL, SOD, and CAT by 13.39%, 5.19%, and 11.16%, respectively. Additionally, treatment with O3 fumigation and IE3900-MY and E3900-L400 packaging enabled the rapid regulation of in-bag CO2 and O2 levels, reducing the CO2 content by approximately 23.85% and increasing the O2 content by 13.24% compared with those in the PE group. Furthermore, treatment with O3 fumigation and L400 PBAT-HP101 packaging regulated saponin metabolism; after 120 d of storage, although the Rg1 content decreased by 28.24%, the Re and Rb1 contents increased by 23.44% and 52.46%, respectively. In conclusion, combined treatment with O3-MAP technology prolongs the storage period by regulating enzyme activity and saponin homeostasis, and treatment with O3 fumigation and L400 PBAT-HP101 was identified as the most effective in preserving the intrinsic quality and saponin components of fresh American ginseng. These results provide a theoretical basis and technical support for the green preservation of high value-added traditional Chinese medicinal materials.