Abstract: In some areas, the lack of measured hydrological data restricts the water resources evaluation. The lake basin has the typical characteristics of lake in flood season and river in dry season, which increases the difficulty of water resources evaluation in the lake basin. In this paper, two typical study areas, the Nam Ou River in Laos and the Tonle Sap Lake in Cambodia, were taken as examples to establish a distributed hydrological model of the basin by using remote sensing data and reanalysis meteorological products. We explore the evaluation methods on basin water resources when the measured hydrological data were missing or insufficient. The results showed that the distributed hydrological model for water resource evaluation has good applicability. While in the lake basin, it is necessary to consider using the hydrograph curve to calculate the dynamic water surface area of the lake. The research results can provide reference for the study of water resources allocation in ungauged region.