Abstract: Blocky rock slopes are characterized by great slope height, steep faces, well-developed discontinuities, and large variations in discontinuity orientation. Information acquisition and accurate stability zonation for this type of slope have long been difficult tasks in geohazard mitigation. Taking the high and steep Hutouya slope as an engineering case, this study proposes a methodological framework for accurate stability zonation of blocky rock slopes. First, a 3D real-scene model of the study area is constructed using oblique photogrammetry, and slope gradient, slope aspect, and orientations of major discontinuities are extracted. Second, the discontinuities are grouped, and inverse distance weighting (IDW) is used to spatially interpolate point-based discontinuity information and convert it into areal layers. At the same time, a mathematical model for the orientation of intersection lines between rock-mass discontinuities is established through geometric analysis, and the orientations of intersection lines between discontinuity sets are calculated. Finally, the stereographic projection method for rock-mass stability evaluation is integrated with GIS spatial analysis to complete accurate stability zonation of the blocky rock slope in the study area. The application results show that the overall stability of the Hutouya slope follows a pattern of stable conditions in the east and higher risk in the west. Stable areas account for 33% of the total area, basically stable areas for 25%, and under-stable areas for 42%. The under-stable areas are concentrated on the southwestern side of the slope near the highway, followed by the northern side, whereas the southeastern side is relatively stable. This case verifies the feasibility of the proposed method for accurate stability zonation of blocky rock slopes and provides a technical workflow and case support for geohazard risk management of similar high and steep rock slopes.