At present, the relative study on WTO in our country contains a large number of articles, but these researches concentrate on the industry and department effect or advantage and disadvantage of China's accession to WTO, for example, the analysis on farm, motor vehicle, finance, the iron and steel industry and so on. Moreover, in the present literature(for example, the system reform's deepening),the most part only included the qualitative analysis, the modeling quantitative analysis was in the deficiency. The conclusion also was too ideal. And those scholars seem look down upon the obstruction and the hardship will probably be encountered in the institutional change course after China's entry into WTO. In this article, the author attempts to scrutinize the relationship between WTO and the institutional change in our country on institutional economics and game theory: how to review the institutional implication to China's accession to WTO; what this kind of change mechanism is after China entered into WTO; what the obstruction is in the institutional change course. As far as the composition arrangement is concerned,the original is according to the deduce logic order. Firstly, this article introduces institution theory and international institution theory; afterwards, the author would introduce the WTO as an international institution, including its feature, its institutional supply, GATT/WTO international trade institution change and so on. Based on these analyses, the original establishes an analysis model to the China's accession to WTO and its institutional change; Moreover, the author elaborates the institutional change implication of China's entry into WTO and the institutional change mechanism after China's access to WTO, the major institutional changes after China entered into WTO―― property rights change, the market structure change, government behavior change and so forth. The original pays attention to the complexity of the institutional change after China entered into WTO. This kind of complexity embodies the benefit group's influence, the negative factors probably emerge: the institution double track; the negative effect of WTO institution supply and so on. Soon afterwards, the original chiefly takes the outward trade system as the backdrop, act as some case and empirical analysis. Finally, based on the evolutionary game theory, the author analyzes the informal institution changes after China entered into WTO. The article's innovation point chiefly rests with: The original looked upon WTO as one kind of international institution. Based on institutional economics, the article analyzes its feature, generation mechanism and so on, based on the game theory, the author probes into the institution changes mechanism of China's accession to WTO, and establishes a model to analyze the relation between China's entry into WTO and the institution changes; the author reminds people pay attention to the double track institution and the other negative effects. We should attach importance to the obstruction and hardship will be probably encountered, and guard against the double track institution's emergence; the article analyzes the relation between China's entry into WTO and the informal institution changes in this country. As far as method is concerned, the original adopt experiment economics, classic game theory, evolutionary game theory and so on. These are new methods to WTO research in our country.