Rainfall can be partitioned into 3 parts through the vegetable canopy: throughfall, stemflow, and interception. In this study, an experiment was carried out in Pailugou watershed in Qilian Mountains in the arid region of northwest China. In a Berberis diaphana and Caragana tangutica shrub stand, throughfall, stemflow, and canopy interception of 38 rain events were observed from 1 June to 31 September, 2014. Then, we analyzed the characteristics of rainfall canopy partitioning and their influence factors. The results showed that: (1) The throughfall, stemflow and canopy interception of individual Berberis diaphana shrub were 175.2 mm (46.3%), 20.8 mm (5.5%) and 182.6 mm (48.2%), respectively, while those of individual Caragana tangutica shrub were 239.1 mm (65.0%), 15.1 mm (4.1%) and 113.4 mm (30.9%), respectively. Meanwhile, the interception ratio of Berberis diaphana and Caragana tangutica community were 29.3% and 18.6%, respectively. (2) The amount of throughfall, stemflow and canopy interception of individual Berberis diaphana and Caragana tangutica shrub showed a significant positive linear correlation with rainfall amount (P＜0.01). The relationship of throughfall ratio and interception ratio of shrubs with rainfall amount could be fitted with logarithmic curve (P＜0.05). (3) The critical rainfall amounts for the occurrence of throughfall under Berberis diaphana and Caragana tangutica shrub were 1.2 mm and 0.9 mm, respectively. Meanwhile, stemflow generated when the rainfall in early period was 2.0 mm. (4) The interception ratio for 2 shrubs showed that the maximum values were achieved in September, with the second highest values in July, and the minimum values in June and August. In addition, the stemflow ratio changed slightly from June to August, while it decreased obviously in September.