With the advancement of globalization and market economy, geo-economic relation has increasingly attracted scholars' attentions. Trade data, including import and export flows, has dominated the geo-economy research owing to its availability and representativeness. However, this might incline geo-economy research toward trade studies and disregard the importance of other international economic components, such as investment. Combining investment and trade data in doing geo-economic analysis could provide us with a more comprehensive understanding of economic relations between countries. Taking China, the US and Northeast Asian countries as an example, this paper explores the patterns of geo-economic relations between these countries, inspects the driving forces and formation mechanism of the patterns, and also makes comparison between China and the US. As a typical region with unbalanced politics and economy and greatly influenced by both China and the US, Northeast Asia can be a salient sample for geo-economic research. A geo-economic streaming potential model is proposed to evaluate comprehensive geo-economic relations which take into account both trade and investment. The conclusions are as follows. First, from 2000 to 2016, the geo-economic relations between China and Northeast Asian countries were strengthened, during which trade flow constantly occupied the dominating position. However, since 2012, the proportion of investment in geo-economy has increased rapidly. Second, the geo-economic flows between China and the US were the strongest with the fastest growth. The geo-economic flows between China and Japan, South Korea were increasing, while those between China and Russia, Mongolia and North Korea had limited influence. Third, both China and the US had expanding geo-economic flows with Northeast Asian countries and similar distribution pattern. Two major differences are also noted. One is that driving forces are different with China's geo-economic relations driven by trade flows and those of the US driven by investment. The other difference is that China's connections with Russia, Mongolia and North Korea have been strengthened while the US has been trying to maintain strong geo-economic relations with Japan and South Korea.