Abstract: Mixed−dimensional attapulgite clay (MDAPT) is abundant in reserves in Gansu Province, which has been preliminarily applied in soil improvement practices. However, the various major and trace elements confined in clay minerals remain largely inactivated in the forms of binding state, and it is difficult to be directly absorbed and utilized by the plant, which significantly limits its potential for agricultural application. To achieve efficient activation of major and trace elements in MDAPT, oxalic acid was employed as an activator, which combined with the synergistic treatment of planetary ball mill. The effects of oxalic acid dosage on the activation efficiency of major and trace elements in MDAPT were systematically investigated. The results demonstrate that mechanochemistry and oxalic acid possess a synergistic effect on the activation of MDAPT. Among them, mechanochemistry induces, lattice distortion and surface activation of minerals based on high−energy impact, shearing and friction forces generated during high−energy ball milling, thereby exposing a large number of fresh surfaces and active sites. In addition, oxalic acid activation realizes the efficient leaching and release of major and trace elements in MDAPT by multiple chemical actions including acid dissolution, complexation and reduction with the assistance of mechanochemistry. With the increase in the added amount of oxalic acid, the electrical conductivity of the activated MDAPT increased significantly from 29.7% to 62.4% according to ICP−MS analysis, indicating a substantial increase in the content of soluble ions due to their leaching and release from minerals. The wheat cultivation in pot experiments were conducted to further evaluate the application effect of the activated MDAPT on the physical and chemical properties of soil. The results confirm that the application of the activated MDAPT significantly improves both soil properties and plant growth performance. Specifically, cation exchange capacity of soil increases by 24.3%～37.2%, while bulk density decreases by 10.3%～13.8%. Correspondingly, the aboveground fresh weight, aboveground dry weight and root dry weight of wheat increase by 39.6%～62.6%, 9.0%～42.1% and 6.0%～24.7%, respectively, demonstrating an obvious growth−promoting and soil structure improvement effects. This study provides a feasible approach for the high−value utilization of MDAPT and soil improvement.