Based on the data of atmospheric and oceanic temperature, the analysis of the abnormal winter temperature of Jiangnan area and its relationship with the sea surface temperature are made. The results are as below. Jiangnan's winter trends to warm in nearly 50 years, especially since the mid 1980's, its tend coefficient is 0.29 and its period is about 6.3-year and 3.3-year, otherwise, the California sea area is its crucial area.