Based on the 160 stations monthly rainfall data provided by National Climate Center of China Meteorological Administration, the all-India monthly rainfall data provided by Indian Institute of Tropical Meteorology and the NCEP/NCAR reanalysis data, this study is made to investigate the summer Eurasian teleconnection (EU) effect on the relationship between the Indian summer monsoon (ISM) and North China summer rainfall (NCSR) from interannual and interdecadal scales respectively, as well as the associated mechanism.Based on the -0.078 correlation coefficient, the EU and ISM are independent of each other.When it comes to the positive EU phase, the relationship between the ISM and NCSR becomes weak, but strong when it comes to the negative EU phase.During negative EU phases, an anticyclonic circulation appears over Lake Baikal area which is extremely conducive to the northerly wind south of Lake Baikal area, thereby controlling the circulation over North China.As a result, when the ISM is strong, warm moist air from the southwest meets northerly winds and forms a front, which can give rise to North China's rainfall.However, during weak ISM, the circulation over North China is completely dominated by northerly winds, and the water vapor transport channel is completely blocked, which makes rainfall impossible.A strong relationship between ISM and NCSR has resulted from the negative EU phase.In contrast, the ISMR-NCSR relationship is weak during the positive EU phase.