The environment problem in Hei River Basin of Northwestern China, which was caused by the interactions of natural and human systems, was very complex. Only the development and application of integrated tools could we better describe and analyse the ongoing process. In this paper, we introduced the Spatial Modeling Environment (SME) as a powerful tool to simplify the integrated model building. After describing the funtion and architecture of SME, we discussed its application perspective in Hei River Basin. It appeared that in order to achieve an integrated ecologicl economic model which could explore the endogenous interaction between socio-economic and ecological dynamics, researchers should identify the main human factors and spatialize them to make natural and human factors have an identical and fixed spatial-temporal scale. The work of identifying human factors in environment impact assesement was very complex. We introduced the IPAT identity as a useful freamwork for identifying the main human factors.