Abstract: Based on 112stations daily precipitation datasets in northwest china from 1960 to 2004 year, concentrated characteristics of precipitation were analyzed by concentration degree and concentration period in northwest china, The result show that spatial distribution of precipitation concentration degree(PCD) and precipitation concentration period(PCP) exist biggish territorial difference in northwest china. It is proved that PCD show out-of-phase change tendency in the east and west of northwest china, and PCP show out-of-phase change tendency in the south and north of northwest china. It is also found that there are better correlation between PCD, PCP and annual precipitation. Furthermore it is proved that there are better correlation between PCD, PCP and the east Asia summer Monsoon, summer Arctic oscillation in inter-decadal scale.

Key words: Northwest china, precipitation concentration degree, precipitation concentration period, inhomogeneity