<p>The middle reaches of the Bailong River Basin represent one of the most developed areas for debris flows in China. Due to the influence of external geological factors, surface rocks within debris flow channels undergo weathering and accumulate at the base of slopes, becoming a major contributor to the formation and development of debris flow sources in this region. In this study, the Sanyanyu, Luojiayu, and Xiaoshuigou debris flow gullies in Zhouqu County were selected as research sites. In this study, remote sensing time-series data (2000–2022) and dynamic monitoring of rock mechanical parameters across multiple elevations were employed to quantify the spatiotemporal relationship between rock degradation rates and debris flow risk. A risk assessment model was developed based on the dynamic degradation process, which reveals how risk levels evolve in response to cumulative degradation. The study involved a comprehensive investigation of these rocks through field surveys and controlled laboratory experiments, complemented by long-term local meteorological data. We identified 14 key indicators reflecting debris flow channel risk levels, encompassing factors such as rock physical and mechanical properties, topography, geomorphology, and meteorological conditions. Using a hierarchical weight decision analysis method, we conducted a risk assessment of the debris flow gullies in the study area. Additionally, the GWO-SVM method was found to be highly effective for evaluating debris flow risks in the Zhouqu area. According to the results, of the 24 slopes within the debris flow channels, 2 (8.33%) are identified as high-risk, 18 (75.00%) as medium-risk, and 4 (16.67%) as low-risk zones. Furthermore, a systematic framework for assessing debris flow risks in the Bailong River region of Zhouqu has been developed as a significant outcome of this research.</p>