Abstract: WT5,5BZGeo environmental assessment is an important tool in planning and site selection for human engineering activities. The characteristics of various types of urban land uses and criteria for evalnatin of the geo environment are discussed in this paper. A GIS aided geo environmental assessment for urban planning is proposed. by GIS, the method for establishing the geo environmental spatial database and mathematical model for evaluating the adaptability of the geo environment to various types of urban land uses are put forward. Acity located in the Northwest China is taken as an example to demonstrate the effectiveness of the GIS approach and the proposed model.