| Abstract | The existing international trade theory focuses on the mechanism of the international trade, but did not give an effective method to explain a country’s goods export proportion in the world. We think, research of merchandise exports must distinguish commodity structure; whereas the trade of manufactured goods is the most important in international trade, we select the manufactured goods as the research object and establish a theory frame and empirical model for the measuring of a country’s manufactured goods export proportion in the world .Through the large sample test, we get the following conclusion: A country's manufactured goods exports proportion in the world is decided mainly by the amount of its population, population density, population age structure, capital formation, economic development mode, trade cost comparison and profits convert. We apply the above theory and model, soundly explain China's manufactured goods export growth in the 1985-2010 years and simulate its developing in 2010-2050 period in six situations. Then ,We make the following prediction: the 2010-2020 period will still be the golden era for China 's manufactured goods export growth; during the 2020-2030 period ,the global proportion of China 's manufactured goods export will enter into a high level stage, and will reach the historic peak about 25%; before and after year 2030, mainly by the large and swiftly increasing of the dependency ratio of population, the long-term growth trend of China 's manufactured goods exports will be stop, thus China 's manufactured goods exports would enter into a declining stage. |