Geopolitics is the best theory for evaluating the national security and promoting the political diplomacy policies in global society. China and Vietnam have the familiar culture since centuries ago and depend on each other heavily in economic recently and the geopolitics is the most important element of the relationship between those two countries.This paper is not only trying to analyze the Sino-Vietnamese relationship via the elements of geographical location, territorial sovereignty, political system, natural resources, population, history, culture, and economy, from the perspective of geopolitics but also trying to figure out the advantage and limits in the relationship between those two countries during Hu Jintao's administration.In the end, this paper will be concluded by analyzing the implication from the competition and cooperation of the two countries in regional politics and economic issues and the possible development of Sino-Vietnamese relations in the future