Abstract: The analytic hierarchy process(AHP)method is used to assess three sub-systems-rock, soil and water-that influence the quality of the geo-environment of the Sanjiang plain. By analyzing the major factors that define the three sub-systems,a hierarchical structure model of the sub-system and a quality index mathematic model are constructed and the quality indices of the three sub-systems are obtained. Then the geo-environmental quality of the three sub-systems is assessed with the AHP and index model.On that basis, an integrated hierarchical structure model and a mathematic model for the systematic quality assessment of the geo-environment are constructed and the geo-environmental quality index is calculated.Finally the quality of the study area is evaluated.The results show that on the whole the geo-environmental quality of the Sanjiang plain is good.