Regional groundwater environment often has serious historical pollution problems in metallurgical industrial areas, which were mining and smelting for a long time under complex hydrogeological conditions. The difficulties for environmental impact assessment researchers usually refer to hard to accurately identifying the target aquifers which were polluted by the project probably, and objectively evaluating regional groundwater pollution status. The metallurgical construction project groundwater environmental impact assessment in Hunan province was taken for example, and visible solutions of the mentioned problems were put forward. Through sufficient investigations of various information, the regional groundwater system was divided and the system which will be polluted. On the basis of analyzing historical groundwater dynamic data, it is practical to confirm the target aquifers of the system and their runoff and discharging conditions. The purpose of ascertaining regional groundwater pollution status was to recognize existing historical pollution objectively, and predict the transport trend of pollutants reasonably. Therefore, comparing with groundwater background values and groundwater quality data of different periods to analyze pollutants accumulation and transportation characteristics was the vital method of the groundwater status assessment. At last, the problem was discussed, how to use the result to guide status survey and the future impact forecast.