Abstract: Traditional landslide stability analysis methods often fall short in the refined assessment of small- and medium-sized reservoir accumulation layer landslides, particularly in insufficient quantification of local hazards and low accuracy of multi-condition coupling simulation. To address these limitations, it proposes an integrated analytical approach based on deep coupling of unmanned aerial vehicle(UAV)oblique photography and FLAC3D. Taking Nanjing Jinniu Lake Reservoir as an example, we constructed a high-precision 3D model by using UAV oblique photography data with borehole investigation and laboratory test results, accounting for the complex terrain features of the landslide(e.g., steep back wall, front reservoir bank, and vegetation-covered middle section). Multi-factor coupling simulations were conducted under five typical working conditions: normal water level, sudden rise of reservoir water level, sudden drop of reservoir water level, rainfall, and earthquake, to systematically analyze the multi-field coupling instability mechanism and sensitivity patterns. Results indicate that the coupled method of UAV oblique photography and FLAC3D outperforms traditional approaches significantly in terms of terrain modeling accuracy and depth of stability analysis.