The formation of desert shrub sand piles (nebkhas) is attributed to the obstruction and subsequent deposition of migrating sand by the shrub itself. However, the relationship between sediment particle size distribution and shrub branch architecture remains inadequately understood. In August 2020, field investigations were conducted on Tetraena mongolica Maxim. shrubs in the Bayan Engger Desert Nature Reserve, located on the Ordos Plateau in Inner Mongolia Autonomous Region, China. Crown morphological parameters of T. mongolica shrubs and associated nebkhas were systematically measured alongside branch architectures. A one-way analysis of variance (ANOVA) was used to identify differences in branch architectures among various levels, while correlation analysis and model fitting were applied to establish the relationship between crown and nebkha morphological parameters. Path analysis was utilized to identify the key branch architectures that influence crown development. Furthermore, sediment redistribution characteristics of nebkhas were quantified, and principal component analysis combined with regression models was utilized to elucidate the contributions of key branch architectures and sensitive particle size fractions to nebkha deposition. Results indicated that the step-by-step branch ratio (SBR) initially increased from the lower branches to the outermost branches before subsequently decreasing. Additionally, branch angle significantly increased (P<0.0500), whereas both the branch length and the ratio of branch diameters (RBD) significantly decreased toward the exterior of the shrub (P<0.0500). Expansion of crown area significantly enhanced nebkha volume, demonstrating a strong linear relationship (P<0.0010). As the primary contact surface for trapping wind-blown sand, the silhouette area of the shrub initially increased and then decreased from bottom to top. Notably, the silhouette area of the 10-30 cm height layer played a crucial role in promoting nebkha volume expansion (P<0.0100). Path analysis further revealed that the key branch architectures promoting crown area expansion were the step-by-step branch ratio between the third-level and fourth-level branches (SBR3:4), followed by the fourth-level branch length (BLL4), the third-level branch angle (BA(L3)), and the ratio of branch diameters between the fourth-level and third-level branches (RBD4:3). Under the continuous interception of sediments by branches and leaves, the proportion of surface sediment with a particle size of 100.00-250.00 mu m reached 51.07%, indicating a significant increase in fine-sized particles. Further analysis confirmed that SBR3:4, BLL4, BA(L3), and sediments within the 50.00-100.00 mu m particle size range were the primary contributors to nebkha deposition. These results demonstrate that the branch characteristics of T. mongolica shrubs near the ground surface promote fine sediment accumulation and nebkha development by regulating crown expansion. The findings reveal the unique adaptation mechanisms of rare and endangered plants in nebkha microhabitats and provide a scientific basis for ecological windbreak and sand-fixation projects in the desert transition zones of arid and semi-arid regions.