<p>Resolving the dynamic evolution patterns and morphological details of surface weathering in earthen heritage sites remains a critical challenge in conservation research. While existing methods are often limited to assessments at single time points and have difficulty in resolving the evolutionary characteristics of multi-scale weathering morphology, this study proposes a dynamic quantitative characterization method integrating three-dimensional scanning technology and wavelet transform theory. Focusing on the Suoyang Ancient City in Gansu Province, China, indoor wind erosion simulations were conducted under four conditions (90° incidence angle, 45° incidence angle, Na₂SO₄ salt migration, and NaCl salt migration). High-precision 3D scanning (Artec Space Spider, resolution 0.1 mm) was employed to acquire surface topography point cloud data. Multi-order decomposition of profile lines using Daubechies wavelets (db8) enabled the extraction of first-order (low-frequency undulation) and second-order (high-frequency roughness) parameters (<i>R</i>_<i>p</i> and <i>G</i>(<i>i</i>)), revealing the dynamic mechanisms of differential weathering. Key findings include: 90° incidence angle induced the maximum recess depth (1.756 cm at 11 min), while Na₂SO₄ salt migration caused the highest increase in wind erosion area (34%) due to powdering effects. Dual-scale roughness analysis demonstrated continuous growth in macroscopic undulations but fluctuating declines in microscopic roughness caused by aggregate detachment, explaining the “initial increase followed by decrease” trend in overall roughness. This method provides a novel tool for dynamic assessment of weathering and optimization of conservation strategies. Future work will integrate environmental factors such as temperature, humidity, and salt cycling to enhance model universality.</p>