Aims In the arid regions of China, the large-scale establishment of artificial shrub forests has contributed to the degradation of herbaceous plants; however, the underlying ecological processes driving this degradation remain unclear. This study aims to investigate changes in root architecture, soil macropore, and mineral particles structure, as well as their intrinsic relationships following the establishment of artificial shrub forests in these areas. The objective is to identify the causes and processes leading to herbaceous plant degradation. Methods Five treatments were established based on the stand age of Caragana korshinskii: control grassland, 9-year-old, 14-year-old, 24-year-old, and 35-year-old forests. A total of 36 ring-cutter samples were obtained. After CT scanning all samples, the built-in modules of Avizo 2024.2 software were used to calculate parameters related to root systems, soil macropores and mineral particles. Results Following the introduction of Caragana korshinskii, the root-soil system network became denser, as evidenced by higher root surface area density, volume density, mean equivalent diameter, and connectivity in Caragana shrublands than in control grasslands. Surface area and volume densities of both soil macropores and soil mineral particles were significantly positively correlated with stand age (P < 0.05). Notably, while thicker primary roots were commonly observed, the number of fine root clusters decreased correspondingly. In heterogeneous environments, soil mineral particles exert a significant positive impact on soil macropores, while plant roots exhibit a significant positive effect on both macropores and soil mineral particles. Roots indirectly promote the formation of soil macropores by facilitating the development of soil mineral particles. Conclusions After the introduction of Caragana korshinskii, the water and nutrient resources concentrated around the coarse root systems of the shrubs in the initial stage limit the resource availability of adjacent herbaceous plants. Following short-term competition (0-24 years), the potential long-term soil improvement promotes the partial recovery of herbaceous vegetation in the late stage after Caragana korshinskii introduction (after 35 years).