The interdecadal variations of the interannual teleconnections betwe en area rainfall in the south of Jiangsu in summer and the 500 hPa hei ght field anomalies over the Northern Hemisphere are studied based on both sets for two periods 1961～1980 and 1981～2000. The researches show that the differ en ce of the teleconnection distributions for two periods is dominant, in which th e intensity of teleconnection is stronger for the latter period than the former. It is resulted from the effects of Pacific decadal oscillation (PDO) on the i nterannual relationships between the East Asian monsoon rainfall and circulation , which are closely related to the interaction between interannual and interdec adal variations.