Abstract: Drift behavior is an important biological adaption of macroinvertebrates in the lotic ecosystems driven by the hydrological process. The drift behavior plays a key role in the studies of spatial and temporal distribution of macroinvertebrates in streams. It is of great significance for understanding the formation process and evolution mechanism of the vertical pattern of river ecosystems. In order to identify the community structure of the drift macroinvertebrates, reveal the drift behavior rhythms, and compare their functional feeding groups, the drift macroinvertebrates were sampled and studied from two tributaries of the Xiangxi River (Jiuchong River and Gaolan River) in August 2017. The results show that Ephemeroptera was the dominant taxa with relative abundance of 76.9% and 96.1% in the Jiuchong River and Gaolan River, respectively. The taxa richness of the drift macroinvertebrates was much higher in the Jiuchong River (35 species) than the Gaolan River (14 species). The dominant species taxa were Epeorus sp., Drunella sp., Baetis sp., Baetiella sp., Ecdyonurus sp., Limnophilidae sp., Philopotamidae sp. and Simulium sp. in the Jiuchong River. And the dominant taxa were Baetiella sp. and Epeorus sp. in the Gaolan River. The nocturnal drifting pattern was identified and the highest density of drift macroinvertibrates appeared at 06:00 in those two rivers. The primary nocturnal drifter was taxa of Plecoptera in the Jiuchong River and taxa of Ephemeroptera in the Gaolan River. In comparing with the drift behavior of different taxa, the drift patterns were more species-specific. Five taxa showed similar drift behavior and the highest density appeared between 20:00 and 22:00, including Epeorus sp., Drunella sp., Ecdyonurus sp., Limnophilidae sp., Philopotamidae sp. and Simulium sp. The highest density of Baetis sp. appeared between 04:00 and 06:00. The highest density of Baetiella sp. appeared between 04:00 and 06:00 in the Jiuchong River, and between 02:00 and 04:00 in the Gaolan River. The composition of Functional Feeding Groups (FFGs) and Habit Traits Groups (HTGs) variated between the day time and night time. However, collector-gatherers and swimmers dominated the FFGs and HTGs. Our studies show that human disturbance plays an important role in structure the drift behaviors and rhythms between the Jiuchong River and Gaolan River.