In order to understand the effect of intercropping pattern with different spacing arrangements on soil stoichiometry and enzyme activity. Four land-use patterns were selected in this study, including S (soybean pattern; Glycine max), P (poplar pattern with 3 m x 7 m spacing arrangement; Populus deltoides), PSN and PSW (poplar-soybean intercropping pattern with 3 m x 7 m and 3 m x 14 m spacing arrangements, respectively). Soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), available phosphorus (AP) contents, stoichiometric ratios and enzyme activities were analyzed at four layers (0-20, 20-40, 40-60 and 60-100 cm) of four sampling sites (0, 1.5, 2.5 and 3.5 m from tree row in P and PSN patterns and 0, 1.5, 3.5 and 7 m from tree row in PSW pattern) in four land-use patterns. The results revealed that SOC:TN, SOC:TP, and TN:TP ratios and Urease (UR) and Sucrase (SU) activities among four land-use patterns ranked as: PSW > PSN > P > S, with the highest value in the PSW pattern (P < 0.05). Conversely, the AN:AP ratio and alkaline phosphatase (ALP) were the highest under the PSN pattern. Additionally, a decreasing trend in SOC, TN, and TP contents, SOC:TP, TN:TP ratios, and enzyme activities was observed with increasing soil depth and distance from trees (P < 0.05). Significant correlations were observed between soil physicochemical properties, enzyme activities, and soil stoichiometric ratios, except the SOC:TN ratio (P < 0.05). Structural equation modelling demonstrated that intercropping pattern and planting spacing affected soil stoichiometry mainly by changing soil aeration conditions. In conclusion, intercropping patterns considerably increased soil stoichiometric ratios and enzyme activity, especially in a wide spacing arrangement. Soil aeration condition is the dominant driver affecting soil nutrient transformation. Our results provide a reference for optimizing land-use patterns and promoting soil quality.