Abstract: Based on the daily rainfall dataset of 565 stations for the period of 1961～2005, graded summer rain days are investigated using the linear regression method. The precipitation amounts are classified into six grades or intensities according to daily precipitation rates, namely, trace (no amount), slight(≤1.0 mm/d),small(1.1 ～ 9.9 mm/d), large(10.0 ～ 49.9 mm/d), heavy(50.0 ～ 99.9 mm/d), and huge( ≥ 100 mm/d) precipitation. Together, the last four grades constitute to a so-called effective precipitation(≥1.0 mm/d). The geographical characteristics for each graded rain day are identified. The results show that the spatial distribution of trace precipitation day is separated by the Northernmost boundary of the East Asian Summer Monsoon with more rain days in the west part of China. The number of efficient precipitation day is the least in Northwest China and it gradually decreases from South and Southwest China to North China. According to the results of rain day trends, the efficient precipitation day increases in the Yangtze River valley and Northwest China such as the Xinjiang Region, but a decreasing trend is found in the Yellow River Valley. The trace precipitation day shows a negative trend in most parts of China. The positive trend of efficient precipitation day in Northwest China is mainly attributed to the small precipitation days, while it is mainly contributed by large and heavy precipitation days in Yangtze River Valley and the area between lower reaches of the Yangtze and Huaihe River valleys. The negative trends of efficient precipitation day over Southwest China and region on the rim of the Bohai Sea are mainly resulted from large rain days.