Abstract: On the basis of present economic, social and ecological conditions, development trend and existing problems in Tongbai county, 13 events in eco-environment of the county have been summarized by application of grey system theo ry. Two objects (need and feasibility) have been selected. In view of the 13 events, 46 coutermeasures have been proposed. By the method of grey sorting optimal decision, the plan of the county’ s ecological environment has been made. Thus the optimal decision for harnessing and protesting eco-environment of the county has been provided.