In the practice of water resource management, the effects of land use and climate changes on basin scale water regime have become increasingly concerned, for which data are not directly available. Despite their simplicity, lumped conceptual model can effectively represent the major hydrologic processes based on limited data and a modest numbers of parameters. A coupled MIKE 11 HD/NAM modelling system was constructed to simulate the rainfall-runoff process of Naoli River Basin in northeastern China. Results showed that MIKE 11/NAM was capable of simulating the rainfall/runoff process of Naoli River Basin. Model performance in validation period was generally better than that in calibration period, which was mainly caused by the modification of underlying surface characteristics due to intensive human activities. The ongoing agricultural development since 1950 had significantly changed the hydrological regime of the watershed, and there was no sign that the wetland degradation trend had stopped recently. The uncertainty of our conceptual model comes mainly from input data, model structure and the selection of optimal parameter set.