Abstract: Under complex terrain conditions, the wake of a wind turbine propagates across terrain units with varying slope aspects and gradients when the inflow direction changes. This leads to significant variations in the vertical distribution of wake velocity. The present study aims to reveal the dominant role of topographic features in the vertical evolution of the wake. A 5 m resolution digital elevation model and a full-scale wind turbine model are adopted. The Reynolds-averaged Navier-Stokes equations combined with the SST k-ω method are employed to simulate the wake flow field. Two typical terrain conditions are considered: a single-peak-dominated terrain under 0° and 180° inflow, and a double-peak-dominated terrain under 30° and 210° inflow. The numerical method is validated against unmanned aerial vehicle measurement data. The results show that the terrain markedly alters the inflow conditions. The windward slope acceleration increases the inflow velocity ratio to 1.09, whereas continuous upstream undulations cause momentum depletion to 0.93. The wake centerline undulates in response to the downstream terrain. It migrates toward the near-surface layer when entering a descending slope and its descent decelerates when entering an ascending slope. The sensitivity of the wake to the slope depends on the inflow state. Under low-momentum inflow, the wake is highly sensitive to slope variations and descends sharply and persistently. Under high-momentum inflow, the slope effect is suppressed, resulting in a gentler descent over a longer distance. In summary, topographic features exert a significant modulating effect on the vertical displacement of the wake. During layout optimization, the variation trend of the wake centerline should be analyzed together with the terrain profile. This helps to reduce the risk of power generation loss for downstream turbines.