Abstract: There are many factors to consider in site selection，and once determined，it is extremely difficult to change. In order to optimize the site selection of 5 tailings dewatering plants provided by a phosphate mine，the main factors affecting site selection were analyzed from the perspectives of technology， economy，environment and national policy，and the evaluation system of dewatering plant site selection scheme was constructed，which was composed of one target layer，three criterion layers and thirteen standard layers.According to the scoring method，the index is quantified and the rating criteria are given，and the technical and economic comparison and analysis of the advantages and disadvantages of the five site selection schemes are carried out，and the Scheme 1 which is restricted by environmental protection policies is excluded. Finally，the matter-element model is used to further optimize the four schemes，and the optimal site selection scheme is determined as Scheme 3. The results can provide reference value for the final selection of the site selection scheme.

Key words: site selection scheme, evaluation system, matter-element model, scheme comparison