Abstract: China's surrounding geopolitical environment is extremely complex, the geopolitical environment analysis and research based on the spatial differentiation are needed. Existing geopolitical environment studies, however, neither put forward a complete geopolitical environment regionalization methods, nor give a corresponding geopolitical environment regionalization map. This study integrated geopolitics, international relations, geography and other disciplines’ knowledge, and draw lessons from the conventional regionalization method in geography, then build a geographical spatial unit regionalization method. The method consists of three parts, regionalization principle, process and multi-index comprehensive evaluation model. With this method, the four countries (India, Pakistan, Nepal and Bhutan) of South Asia are divided into four levels of geopolitical environmental unit, 19 of level 3 units and 9 of level 4 units. The results show that, this method helps to quickly grasp the overall pattern of surrounding geopolitical environment, especially deepen the understanding of geopolitical environment situation in the key areas.