The climate research was focused mainly on change of average temperature and precipitation.Extensive researches showed that extreme climate events caused tremendous economic loss,so they were concerned by public.Based on daily precipitation datasets from 314 stations in China from 1955 to 2004,the extreme strong precipitation threshold of different stations were defined by centesimal value method.Firstly,year after year extreme strong precipitation events were counted up at different stations,then extreme strong precipitation event concentration degree (ECD) and concentration period (ECP) which reflect time distribution fea-tures were introduced,finally,intra-annual inhomogeneity characteristics of extreme strong precipitation event were analyzed by the new parameter in China.The result shows that average spatial distribution of ECD and ECP displays a “low-high-low” characteristic from Northwest China to the Southeast China,Xinjiang is the weakest region of ECD,Xizang (Tibetan) Plateau is the strongest region of ECD;and Southeast China is the earliest region of ECP,while Southwest China,central North China and centrel Northeast China are the latest region of ECP.It is proved that relative greater regional difference exists in the anomalous spatial distribution of ECD and ECP.In terms of regional average,western Northwest China the most scattered region of ECD,and Northeast China is the most concentrated region of ECD.It is also found that ECP is equivalent in Northeast China,eastern Northwest China,North China and the Qinghai-Tibet Plateau,which is apparently later than that of the other regions.The middle and lower Yangtze River is the earliest region,in addition the long-term tendencies of ECD and ECP are inconsistent in various regions,but their period of vibration characteristic is basically consistent.In recent 50 years the change of ECP showed a 2-4yr,7-9yr and 13-15yr period of vibration and the change of reflected a 2-4yr,6-8yr and 11-13yr period of vibration in various regions.