With the increasing dependence on the economic system of international financial market, China's main board market, which can be regarded as a barometer of China's economy, also shows its relevance to the international stock market. August 2015 August 18 - 25, five trading between Chinese, American and Japanese stock market ushered in the stock market crash will this issue once again pushed to the attention of the platform.This issue mainly through the Chinese Shanghai Composite Index and the U.S. Dow Jones Industrial Average Index from 2005 -2015 10 years of stock index data contrast, and then determine the U.S. stock market impact of the general law of China's A shares. Through the simple understanding of the linkage model of the domestic and foreign economists and the empirical test, the correctness of the general law is proved according to the analysis results. The main conclusions are as follows:First: the U.S. stock market has a strong impact on China's stock market. Although the economic environment of developed countries started late, but the development model has become mature, the strong linkage between the various developed countries, China's economic market is still in a state of imperfect, relatively speaking, it should be more influential, and must be accompanied by China's macro-control policies;Second: the impact of the stock market in China and the United States is being affected by the impact of a single American stock market on the Chinese stock market and the stock market. This reverse effect is still in the bud, but in the rapid economic growth of China's economy, China's impact on the United States will also be more and more.