Rainfall was partitioned into three parts through the vegetable canopy: Throughfall

stemflow and interception. This process played a determining role in water balance for forest stands and in regulating processes of this mountainous region. In present study

the experiment was carried out in Pailugou watershed in Qilian Mountains

in the arid region of Northwest China. In a 96-year-old Picea crassifolia forest stand

throughfall

stemflow and canopy interception of 34 rain events were observed from May 1 to September 31

2015. Meanwhile

the related meteorological factors

including air temperature (T)

air relative humidity (Rh) and precipitation (P) were simultaneously monitored by an automatic meteorological station in the outside forest. Then

we analyzed the characteristics of rainfall canopy partitioning and their influence factors. The results showed that: (1)During the total observation period

the total throughfall

stemflow and interception of Picea crassifolia forest were 275.9

1.8 and 90.0 mm

and accounted for 75.04%

0.48% and 24.48% of the total atmospheric precipitation

respectively. Meanwhile

their ratios varied significantly under different rainfall grades. (2)The three parts of rainfall canopy partitioning were significantly correlated with rainfall

rainfall duration

maximum rainfall intensity in 10 minutes and relative air humidity. With the increase of rainfall and rainfall duration

throughfall and stemflow would constantly increase and their ratios would become more and more stable. (3)The critical rainfall amounts for the occurrence of throughfall and stemflow were 0.8 mm and 9.6 mm respectively. Therefore

we concluded that meteorological factors were the important factors of rainfall canopy partitioning.