This paper tries to model the stock return in the United States and China separately, using SP 500 index and CSI 300 index respectively as modeling subjects, by adopting the Generalized Least Square (GLS) model and Autoregressive Conditional Heteroskedasticity (ARCH) model. The closing yield of 10Y treasury bond and 10Y corporate bond, the closing price of the commodity index, and interbank offer rate overnight are employed as independent variables. Residuals from two models are formulated by the ARCH model. This process visualizes and predicts the volatility in the market. The models reveal the relationship between the performance of other asset classes and stock return in the United States and China. These will help investors and portfolio managers to allocate their positions and guide their investment strategy by forecasting the volatility in the market.