According to the relationship between the snow cover in Tibetan Plateau and Eurasia in winter and the summer rainfall in China, the correlation between the summer rainfall in China and the snow cover in Plateau and Eurasia is verified. Results indicate that the prediction of summer rainfall is better by snow cover over the Plateau than that over Eurasia. The flood of the Changjiang River valley in summer usually occurred when anomalous snow cover in Tibetan Plateau is above normal in winter. This is an important indicator for the prediction of rainfall in summer.