Abstract: Overshooting tops are turret-shaped cloud structures that form when strong updrafts in deep convection penetrate the tropopause and extend into the stratosphere, and they are closely associated with severe weather conditions such as heavy rainfall, hail, and strong winds. A comprehensive analysis of its spatial distribution is essential for enhancing the monitoring and early warning capabilities of severe convective systems. The southern terrestrial region of China and the South China Sea are regions with frequent severe convective activity in China, where convective and lightning activity characteristics show distinct land-sea contrasts due to variations in underlying surface conditions. Utilizing multi-spectral cloud radiative data from Himawari-8 geostationary satellite, an effective algorithm is developed to extract the contours of overshorting tops. The algorithm is evaluated using overshooting top measurements from Global Precipitation Measurement (GPM) radar during its overpasses of the southern terrestrial region of China and the South China Sea from 2019 to 2023, achieving a probability of detection (POD) of 87.7% and a false alarm ratio (FAR) of 31.4%. Compared to the traditional single-channel infrared texture algorithm, FAR is reduced by 62.0%. Using this algorithm combined with lightning data located by Hybrid Lightning Sferic Array obtained during Guangdong Comprehensive Observing Experiment on Lightning Discharge, the distribution and evolution of overshooting tops over the southern terrestrial region of China and the South China Sea are statistically analyzed for the period from May to October during 2019-2023, and the land-sea contrasts are also examined. Results indicate that, over the South China Sea, overshooting tops mainly concentrate in the northeastern sector, with brightness temperatures generally below 192 K and locally reaching 184 K. The occurrence frequency in this maritime region is 2.9 times higher than that over the southern terrestrial region of China, where overshooting tops are primarily distributed over northern Hainan Island, central-southern Guangxi and southwestern Guangdong, exhibiting relatively higher brightness temperatures of 186-195 K. Statistical analysis reveals that 8.9% of thunderstorm clouds over the South China Sea develop overshooting tops, whereas the proportion decreases to 6.6% over the southern terrestrial region of China. Overshooting tops over the South China Sea maintain a relatively high occurrence frequency from June to October, whereas those over the southern terrestrial region of China are mostly active in July; overshooting tops over the South China Sea are more evenly distributed throughout the day, with no evident day-night differences, whereas those over the southern terrestrial region of China develop rapidly in the afternoon and weaken quickly during the night.