Abstract: To evaluate the pollution situation and variation tendency of quality of Weihe River in Baoji Section, using fuzzy synthetic evaluation method to evaluate the water quality of Baoji section of Weihe River based on the observation data of six river segments during 2007-2009. Using rank correlation coefficient method to quantificationally analyze the water quality transform trend of the main three segments during 2002-2009. The results showed that the overall quality of source water achieved to the relevant functional areas of water quality categories, nevertheless organic pollution of source water could not be ignored; the pollution trend of Baoji section of Weihe River was descending; the water quality of Linjiacun segment was the best of all, and then were the Shengliqiao, Changxingqiao and Wolongsi segments, the other segments were the most serious.