Abstract: The Dongjing distributary is an important floodway of releasing the Hanjiang River flood in the lower Hanjiang River into the Yangtze River, its variation of flow and sediment diversion not only affects the flood control, water resource utilization and navigation of this basin, but also affects the flood control of the Hanjiang River and the Yangtze River. Based on a large quantity of measured hydrological data, the laws of runoff and sediment diverted from the Dongjing distributary were systematically analyzed. The results showed that: the average annual 4.25 billion m3 water was discharged into the Dongjing Distributary, accounting for 9.1% of the Hanjiang River, and the flow diversion ratio changed obviously since the completion of upstream Danjiangkou Reservoir; the average sediment of 5.835 million t was discharged, accounting for 13.5% of the Hanjiang River, the average sediment of 5.835 million t was discharged, accounting for 13.5% of the Hanjiang River; the flood peak flow diversion ratio was reduced from 22.7% to 17.9%. By the regulation of Danjiangkou Reservoir, the days of zero-flow were reduced. In addition, affected by clear water discharging, the river bed of the Dongjing Dstributary was obviously scoured and the dry-up water level fell. The research results have a certain reference value for the river regulation, water resource utilization and flood control of the Dongjing River and the middle and lower reaches of Hanjiang River.