Water resource plays an important role in social and economical activity in China, especially in northern arid or semi-arid regions. In the ungauged Lake Hulun basin, an approach combining two-parameters monthly water balance model and mass balance equation was developed in the study to reconstruct the hydrological and salinity series. 42-years hydrological and salinity monthly series are reconstructed in the Lake Hulun using the model. Simulated water level and salinity are in good agreement with the observed annual mean data. The estimation of water resources and salinity is reliable, and supports the solid base for wise management of water resources in Lake Hulun.