[Objective] The effects of different agroforestry systems on soil physical properties, especially carbon sequestration, in the Yellow River flood plain was determined, in order to provide scientific guidance for optimizing regional agroforestry systems in the future.[Methods] Soil physical properties and carbon sequestration characteristics were analyzed in a Chines ash (Fraxinus chinensis) plantation under different agroforestry systems. Soil samples were collected from an ash plantation located in the Dongming National Forest Farm, Shandong Province, China. The following agroforestry systems were evaluated:ash and chrysanthemum (BJ), ash and peanut (BH), ash and soybean (BD), and ash alone (as the control, CK).[Results] ① The BD system significantly reduced soil bulk density in the 0-20 cm layer (7.4%~13.2% lower than the other systems), with bulk density following the order of CK>BH>BJ>BD. The BD system also increased soil total porosity (2.3%~19.8% higher), improved soil water retention ratio, and improved soil structure; ② The BD system had the strongest soil carbon sequestration capacity (14.54 t/hm² higher than that of CK). Soil carbon sequestration increased with soil depth, and was more conducive to enhancing soil fertility and improving soil quality.[Conclusion] In the carbon neutral mode, the BD agroforestry system should be the focus of agroforestry management in the Yellow River flood plain, because this system not only improves the regional ecological benefit, but also promotes the green development of agriculture and forestry.