Taking America's implementing the Asia-Pacific rebalancing strategy and China's building the Silk Road Belt as a backdrop, this research generalizes the basic concepts of geopolitics, geo-economy and geo-strategy, and then reviews the basic theories of geopolitics and its progress. Furthermore, based on the results of analyzing the features of changes of East Asia geopolitical environment, the paper summarizes the development trends of geopolitical environment of Sino-Mongolia and Sino-Russia, and considers that the geopolitical pattern and order of the South China Sea has been changed deeply with the strong involvement of USA. One of the most important changes is that China's interests are suffering stern challenge from Japan, Vietnam, Philippines and other countries. Afterwards, taking the energy market as an example, this research analyzes the impact of geopolitical changes of East Asia on the regional resources market. For China, the strategic conception of building the Silk Road Economic Belt is a countermeasure to counterbalance the adverse changing. At the same time, Russia was sanctioned by western countries and turned their eyes to Asia. So the stern geopolitical environment of both countries provides a good opportunity for China-Russia economic and trade cooperation. Because of the similar geopolitical situation and economic complementary, the energy cooperation between China and Russia is expected to be further enhanced in the future. Although Mongolia's economy relies heavily on China, its geopolitical strategic demand and strategic target have changed profoundly since the United States returns to Asia. The diplomatic priority of Mongolia is to strengthen exchanges with "the third neighbor" and to counterbalance its two neighbors' influences. Though the Sino-Mongolia geopolitical relations are mainly positive, America's involvement increased the uncertainty of Sino-Mongolia resources cooperation. For Japan and Korea being America's allies, the harsh regional geopolitical environment will decrease their share of resources market in northeast Asia in the future.