Hu Huanyong is one of the founders of modern Chinese human geography, a pioneer of geopolitical research and an outstanding thinker of geostrategy. This paper evaluates Hu Huanyong's geostrategic thought in the context of the changing international geopolitical environment in which China has embarked upon its path of national development. Hu Huanyong is believed to be the pioneer and visionary geographer who has long-term influence on China's geopolitical research and the formulation of China's geostrategy. He is credited for his systematic demonstration of the Chinese sovereignty over the islands in the South China Sea, namely the Nansha Qundao, Dongsha Qundao, Zhongsha Qundao, and Xisha Qundao, particularly his first naming of Nansha Qundao. He is ahead of his times with his comprehensive study of China's geopolitical environment, his prediction of the inevitable Japanese invasion into China and armed conflicts between Japan and the US, and his call for special attention to border governance and national security and defense. He has strongly advocated the recovery of the Ryukyu Islands, stressed the role that geographers play as the vanguards of China's territorial development, and called for a better integration of geography with national defense education. The paper concludes with an observation of the great significance to inherit and carry forward Hu Huanyong's geostrategic thought in the current global geopolitical environment characterized by unprecedented changes of the world in a century and the great rejuvenation of the Chinese nation.