Land desertification is a natural process driven by multiple environmental stresses, which leads to environmental deterioration and diminished agricultural productivity. As environmentally friendly alternatives, biopolymers have emerged as promising materials for soil stabilization and erosion control. In this study, guar gum (GG) was employed to stabilize desert soil, and a series of tests were performed to investigate its mechanical behavior, erosion resistance, and microstructure. The results revealed that the GG content significantly influenced the unconfined compressive strength (UCS) and shear strength of the soil. Specifically, the UCS, cohesion, and internal friction angle of the stabilized soil all achieved their maximum values at 2.0% GG content. Surface characteristics, cumulative erosion weight, and erosion rate confirmed the capability of GG to mitigate rainfall-induced erosion. Furthermore, field tests demonstrated its efficacy and potential to resist wind erosion, and a surface crust formed on the GG-stabilized soil. Additionally, the stabilization mechanism of GG primarily involved cementation, filling, and encapsulation, resulting in a reshaped soil structure, thereby enhancing its strength and overall stability. The research results will provide an eco-friendly strategy for erosion control in desert soil areas.