A numerical hydrological model that is universally applicable in large low plain area is developed. In this paper, common characteristics of large basin area such as channel network connecting with lakes and ponds are described in detail and the hydrological processes can be simulated by the numerically combined method between two-dimensional model for large lake and one-dimensional model for channel network. This model has been calibrated against the observed data in 1984 and 1985 from May to September in Taihu Lake Basin, China. From the result, good agreement between simulated water level and discharge to those from the observation data was indicated and therefore, this model satisfies the hydrological processes for practical use.