Based on the analysis of the point-to-point correlation coefficient of the monthly mean 500-hPa geopotential height in the Northern Hemisphere (north of 20°N) from 1958 to 2002, the persistence of circulation is investigated. It is shown that there is a significant persistent area in middle latitudes of Asia, and this area is only one in the extratropics of the Northern Hemisphere. The central area is located in (30°N－50°N, 70°E－110°E), which is over the Tibetan Plateau, the Mongolian Plateau and the Loess Plateau . The persistence varies clearly with season. The persistence between February and March is little, between March and April is little too. Then persistence between April and May increases sharply, the inter-monthly correlation coefficient reaches 0.6; between May and Jun, it increases to 0.8. For summer to early autumn (June－September) every inter-monthly correlation coefficient remains over 0.8 stably. In autumn and winter the persistence weakens month by month, until early spring, reaches the lowest point.  The analysis is made from May to September during the most significant positive persistent seven years and negative persistent seven years in 1958－2002. It is shown that in the most significant positive persistent years circulation pattern “west-high－east-low” appears in middle latitudes of East Asia in summer; in the most significant negative persistent years circulation pattern “west-low－east-high” appears. In the positive persistent years eastern China summer rainfall is “north-below average－south-abundant”; in the negative persistent years summer rainfall is “north-abundant－south-below average”. The mean 500-hPa height anomaly changes from negative persistence to positive persistence during the 45 years, and correspondingly the eastern China summer rainfall pattern changes from “north-abundant－south-below average” to “north-below average－south-abundant”. The day-to-day recognition for weather system shows that high and ridge are prevailing over the middle part of Asia, trough and convergence zone systems are prevailing over the middle and lower reaches of the Yangtze River during the summer of positive persistent years; low and trough are prevailing over the middle part of Asia, subtropical high and southwest pattern are prevailing during the summer of negative persistent years. It is shown that there are two kinds of climatic courses and prevailing weather processes for summer drought and water logging in China. So, this work may be beneficial to predicting summer rainfall trend in China and summer circulation over East Asia in May and June.