This research aims to investigate the differences between e-commerce in two countries, the origins of those differences, and comments on the future of E-commerce of China and US. While China is among the developing countries in Asia, the US has the greatest power to affect global market. By analyzing previous research on E-Commerce, we have concluded the main differences between logistics and payment, legalization and technology, and cultural contents. Also, we predicted that B2C will become the dominating force and ultimately surpass C2C in China.