[Objective] To explore the trend of water quality since the start of the comprehensive regulation project in Shaanxi section of the main stream of Weihe River

in order to check the effectiveness of regulation works and provide technical support for subsequent river pollution prevention and control.[Methods] Based on the water quality data of the main monitoring points in Shaanxi section of the Weihe River main stream during 2010-2016

the temporal and spatial variation characteristics of water quality were analyzed

the trend of water quality was expounded by using Mann-Kendall test

and the future trend of water quality was identified by using R/S analytical method.[Results] From 2010 to 2016

the water pollution had changed from severe pollution to mild pollution. The chemical oxygen demand(COD) and NH3-N concentrations of 4 exit monitoring points in Baoji

Xianyang

Xi'an and Weinan cities during the dry season were generally higher than those in the flood season. After the treatment

the decrease of the pollution in Xi'an City exit section was the most significant

but still was the most polluted section. The concentration of NH3-N in Baoji

Xianyang

Xi'an and Weinan cities showed a significant downward trend

and this trend would continue. The concentration of COD in Xianyang

Xi'an and Weinan City showed a significant downward trend

but the future sustainability was weak. The increasing trend of COD concentration in Baoji City was not significant.[Conclusion] After the comprehensive treatment

the pollution level of the river is obviously reduced and the water quality is changed obviously. However

the concentration of pollutants in some sections shows an upward trend

which needs special attention.