The three-layer variable infiltration capacity (VIC-3L) macroscale hydrological model was applied to simulate runoff in the Laohahe River Basin. The results show that the computed hydrograph is in good agreement with the observed one during calibration as well as validation periods. But in some years, like 1997 and 1999, the model did not perform well. The causes were analyzed in this paper, namely land use and cover change, water taking from river channel, groundwater abstraction from aquifers, and other human activities.