In lunar exploration, especially in polar regions, the influence of terrain occlusion on lunar surface illumination is particularly important. Current calculations of lunar illumination conditions often ignore the shading effects caused by lunar topography and treat the Moon as an ellipsoid for computation, lacking the illumination results affected by high-resolution terrain. In the polar regions of the Moon, most calculation methods yield significant errors, making it difficult to apply them in space mission planning and scientific research studies. This paper proposes a real-time calculation method for lunar polar illumination that considers high-precision terrain. Based on the currently available highest-resolution Digital Elevation Model (DEM) data, this method searches for the horizon and calculates the elevation angle for each azimuth angle, combining it with the solar zenith angle and solar disk apparent diameter to obtain the illumination calculation results at a specific location. This method provides accurate calculations of illumination results and allows for the customization of terrain search range and accuracy. Furthermore, it has the capability to output illumination conditions for any desired time span, providing flexibility in studying illumination patterns over different time periods. Based on this method, several points in the lunar South Pole were selected as candidate landing sites in this study. The annual average illumination levels were calculated for each landing site at heights of 2, 5, 8, 10, and 15 m. The analysis focused on examining the impact of different heights on the illumination conditions.