The study is to assess environmental impacts before and after the renovation project,and to make scientific management decisions. The life cycle assessment (LCA) was used to evaluate environmental impacts load before and after the upgrading and reconstruction project of Hohhot Princess Mansion Wastewater Treatment Plant (WWTP),and to identify and judge the variation of environmental impacts load. The results showed that the environmental impacts of the WWTP after transformation were greater than before, increasing by 63. 5%. The influence potential of water quality and water eutrophication reduced apparently,but the impact potential of non-renewable resources consumption and global warming increased in a great amount. The fundamental reason for the increasing environmental impact load lied in the increase of power consumption. Finally,according to the evaluation results,the improvement suggestions for the upgrading and reconstruction project of the WWTP were put forward.