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Jatibarang Reservoir is located on the Kreo River. This reservoir functions are as a flood controll, water supply and hydroelectric power. The total capacity is around 20.4 million m3. The spillway is designed at elevation +148.9 with a width of 15 m, capacity Q50 = 240 m3 / s, and an emergency spillway at + 151.80 m, width of 60 m with a capacity of 1350 m3 / s. This paper aims to evaluate the performance of reservoirs in their function as flood control, due to land use changes in upstream of the reservoir catchment area. The method which was used is the HEC HMS. Land use map data is used of 2016 and spatial planning map of Central Java province for 2011-2031. The results were obtained the hydrological parameters increase in CN and imperviousness, decrease in initial storage and initial abstraction wich resulting in increased of flood discharge. The impact of this, an emergency spillway that was designed for discharges greater than Q50, must function at discharge that smaller than Q50. Initial design, Q50 water level elevation below +151.8, but with the change in hydrological parameters, water level elevation of Q50 increase up to + 152.2