Abstract: After damming and impoundment of Xiaolangdi Xixiayuan Equalizing Reservoir in 2006, the reservoir had taken part in the water sediment regulation during two years favorably, and its equipments were operated in good condition. But some problems occurred in headstock gear of flood discharge arc gate due to the frequent operation, which includes creep and nonuniform speed. The principle of hydraulic headstock gear of flood discharge gate and its faults were introduced in detail, and some concrete measures for treatment of the faults were proposed.

Key words: hydraulic headstock gear of flood discharge gate, action principle, creep, nonsynchronous of left and right hydro cylinders