Abstract: Debris-flow deposition zones often exhibit evolutionary characteristics such as dispersed sediment particles and deflected morphology due to changes in flow-path configuration. Current research in this field remains insufficient, constraining hazard prevention and comprehensive utilization of deposition zones. In this study, three types of debris-flow deposits with varying densities were employed as prototype materials. Indoor physical model tests were conducted using a self-developed variable-flow-path simulation system under three channel configurations: straight (Type I), curved bend (Type C), and twist bend (Type S). By integrating high-speed photography, distributed sensing, and image processing techniques, parameters including flow velocity, discharge, deposition morphology, thickness distribution, and particle size distribution were simultaneously monitored. Deflection angle and offset distance were introduced to quantitatively analyze flow-path deviation behavior. Results show that flow-path morphology dominates deposition patterns: straight channels form strip-like deposits, while curved channels produce fan-shaped distributions. Deposited particles display longitudinal sorting, with finer grains near the flow path and coarser grains farther away; bends significantly hinder the transport of fine particles. Path deviation is primarily controlled by channel morphology, while flow velocity and material density play regulatory roles at specific stages. This study reveals the movement-deposition response mechanism of debris flows under complex flow paths, providing a scientific basis for risk assessment and mitigation engineering design of debris-flow hazards in mountainous regions.