Flood protection of Fuhe river basin has been payed high attention after Changkai-levee crevasse in 2010. This paper constructions a model of flood disaster lose calculation considering flood disaster and social economic developing based on GIS. Firstly social economic indexes have been selected according to characteristics of the urban and the rural. Secondly a mathematical model of flood routing using Finite Volume Method has been made in spacial information grids, the data of inundated depth and flood duration can be extracted from the grids. In the end ,wo calculate the loss by flood disaster losses calculation process model. This paper solves the stacking problem of flood characteristic and administrative boundaries effectively, which makes a development on accuracy of flood disaster assessment.