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Groundwater residence time is an important indicator of hydrological cycle and essential for water resources development and utilization. In this paper, groundwater resi-dence time in non-flood season, flood season and water year has been determined from daily streamflow hydrograph of ten hydrological stations in Wudinghe River Basin located in the middle reaches of the Yellow River Basin. Results have showed that: baseflow recession constant in Wudinghe River Basin ranges from 0.72 to 0.94 with a larger recession rate in flood season than that in non-flood season. Spatially, the recession rate of baseflow in loess area is the biggest, but is the smallest in the sandy area. The half-residence time of groundwater varies from 1.8 to 45.5 days while overall residence time of groundwater is be-tween 34 and 342 days in different sub-basins of the Wudinghe River Basin. The annual av-erage overall residence time of groundwater decreases from 117 days in the upper reaches to 73 days in the lower reaches.