Abstract: Taking Liuhe River of Taicang as the research object，the single-factor standard index method was used to evaluate the water environment quality. The results showed that in each monitoring section，the water quality monitoring indexes of dissolved oxygen，ammonia nitrogen，total phosphorus，petroleum and lead exceeded the standard commonly，this illustrated that the water quality of Liuhe River has not reached the requirement of surface water quality standard，and the water has been polluted in certain degree. The conclusions of this paper are of great significance for Taicang water supply，water safety and how to implement the objectives management of water quality.

Key words: Liuhe River of Taicang City, single-factor standard index method, water environment quality assessment