With Dow Jones industrial index in US and China Shanghai composite index in China as the empirical target, an analysis has been made of the fluctuation effects in Chinese and US stock markets by using DCC-GARCH model. With its research period ranging from January 1, 2009 to June 13, 2016, the stock price index of the two countries on the common trading day has been selected, thus obtaining a total of 1 708 daily remuneration data. The empirical results show that: China’s stock market is negatively affected by the stock price returns significantly at the previous stage, while the US stock market is positively affected by the previous stock price returns; there is a long-term equilibrium relationship between China's stock market and the US stock market.