<p>Creep-type landslides exhibit slow long-term deformation responses. Deformation is significantly time-dependent, and its mechanical process is controlled by unsaturated fluid–solid coupling. To elucidate the evolution mechanism of landslide deformation, mechanical tests, theoretical derivation, and numerical analyses were performed. An unsaturated fluid–solid coupling model was formulated, considering the creep effect according to the unsaturated visco–elastoplastic model, unsaturated continuity equation, unsaturated permeability function, and deformation effect previously established by the author. Based on the finite element method and the ABAQUS secondary development platform, numerical simulation methods were further established for stress–strain, seepage analysis, and seepage–stress coupling. To verify the accuracy of the coupling numerical analysis method, the Baijiabao landslide in the Three Gorges Reservoir area of China was used as an illustrative example to calculate the displacement field of the landslide under rainfall and reservoir water changes. The results indicate that the numerical prediction values were relatively smooth. Although there were some differences between the numerical predictions and monitored values, the overall deformation trends of the two were essentially, the same in describing the time-dependent characteristics of the stress–strain curve of the creeping landslide. These results provide a novel approach for studying the deformation evolution mechanisms of creeping landslides.</p>