Located in north-south directed mountains and valleys in Southwest China,mainly in Yunnan Province,the Longitudinal Range-Gorge Region(LRGR) is a very important ecological corridor between South China and Southeast Asia.Ecological changes in this region directly influence Chinese trans-boundary ecological security and resources security.In this paper,the spatio-temporal variations of annual precipitation and precipitation in winter and summer over the LRGR are studied using many statistical methods with 1901-2002 precipitation data at 13 stations scattered in LRGR.The results show that the first type of principal distribution pattern of the precipitation is consistently high or consistently low.The distribution of both annual and summer precipitation shows meridionality while longitudinal for winter precipitation.Because of the "corridor-barrier" and orographic lifting function,it is higher in the west of the LRGR while lower in the east of the LRGR for annual and summer precipitation,bounded by Yuanjiang-Honghe river.The center of the distribution is located on the Lancang River for annual and summer precipitation,while that on the Nujiang River for winter precipitation.It is higher(lower)in the northwest of the LRGR while lower(higher) in the southeast of the LRGR for the second type of principal distribution pattern of annual precipitation and precipitation in summer and winter.The variation of the precipitation in the LRGR is characteristic by interannual scale,interdecadal scale and the climate base state for both annual and summer precipitation.For the winter case,the variation of the precipitation in the LRGR is characteristic by interannual scale and interdecadal scale.The significant variation of precipitation concentrates in a high frequency band less than a 3.5-yr period.The climate base state of the time series of the second principal component of annual precipitation is significant and the next is the second principal component of summer precipitation.