Abstract: In this paper, studies are made of the structure and interannual variation of the 500hPa teleconnection between the Bay of Bengal(15°N, 85°E) and the Sea of Japan(40°N, 130°E) during the Northern early autumn and its relation to tropical easterly jet, El Nino and China's precipitation. It is noted that when the height of 500 hPa over the Bay of Bengal increases and that over the Sea of Japan decreases, there is usually the low Southern Oscillation Index or the occurrence of El Nino and the west wind departure at the 100hPa entrance region of tropical east winds. These characteristics cause the deficiency of rainfall in eastern China during early autumn. by using these results, the El Nino events during the recent 40 years and in 1991 can be clearly diagnosed.