The Fuzzy model was established to optimize the comprehensive assessment of water environment, and the weight of the indexes on the water environment was determined. The water quality of Shitingjiang River in 2007--2011 was calculated by Fuzzy model. The results showed that： （1） The water quality in 2007--2011 came up to III functional classification standards, while the water quality was worsening on the trend, the main pollutant was CODMMn. （2） The effect of hydrology factors on water quality was bigger than the else factors, the water quality was polluted badly in withered water seasons. （3） The water quality of exit section was worse than the antitheses section, CODMn came into severe pollution. Especially in withered water seasons, the water quality approached critical value. The main cause of the water environment quality worsening in basin was the excessive discharge waste water with the rapid development of industry, agriculture and urbanization.
Guangdong Agricultural Sciences
fuzzy comprehensive assessment
water environmental quality