Abstract: Based on the summer rainfall data at the southern foot of the Yanshan Mountains and NCEP reanalysis data, by using statistical methods and contrast analysis, the evolutional tendency of summer rainfall at the southern foot was analyzed. The results show as follow: the summer rainfall has shown an obviously linear decreasing tendency of 29 mm/10 a during the past 55 years, an abrupt climate change took place in the later 1970s. And change periods of the summer rainfall differ from those of the East Asian summer monsoon.The decrease of summer rainfall at the mountain foot is mainly due to the change of atmospheric circulation patterns over mid-latitudes of Asia and the Arctic region.

Key words: southern foot of the Yanshan Mountains, summer rainfall, East Asian summer monsoon