Abstract: Neogene loess-red bed landslides are the most typical and concerning disaster in the Loess Plateau. Their failure mechanisms have become a frontier scientific challenge in the field of engineering geology that requires urgent breakthroughs. This study adopts landslide-controlling slope structures as the analytical framework to systematically examine geological structure types and occurrence characteristics of loess-red bed slopes from two perspectives: stratigraphic structures and geological interfaces. It elaborates on the triple control effects of structural planes in landslide formation—boundary confinement, hydraulic channelization, and mechanical weakening—and summarizes landslide types and corresponding failure modes based on structure control effects. The evolutionary mechanisms of landslides under the influence of slope-control structures are comprehensively analyzed. Based on the current state of research, four critical issues are identified: ①How to quantify the spatiotemporal coupling effects between geodynamic forces and the evolution of structural planes? ②How slope structures induce slope instability via cross-scale energy transfer and damage accumulation? ③At what critical state of key physical-mechanical parameters do controlling structures trigger slope failures? ④How to develop multi-field coupled numerical models integrating structural control mechanisms with landslide kinematic linkages? To address these challenges, this study proposes prioritized research directions, which include dynamic evolution processes and governing mechanisms of sliding-control structures under multi-field coupling effects, mechanical deterioration mechanisms of red bed structure planes driven by water-rock interactions, critical state thresholds and diagnostic criteria for structure control in loess-red beds landslides, kinematic evolution modeling of loess-red bed landslides incorporating structure control effects.