During the years of establishing the political regime in the mainland China, Mao put emphasis on setting up a new China in the lines of Marx and Lenin Socialism. In 1978, Deng advocated the so-called “Reform and Opening” and “Socialism with Chinese Characteristics”. China have generated dramatic changes in trade and economic development. At the initial stage of Taiwan recovery from Japanese Colonialism was about US$50 in the Republic of China. At present the income per capita reached over US$10,000. Why have theses differences between the Mainland China and the Republic of China? In this paper, I discussed and analyzed these differences from theory to practice and reviewed the tendency of trade and economic development between the two economics until to now. Along with the views of some scholars. I brought up my own opinion with caution but optimism to show the prospects for Cross-Strait economic development.