[Objective] To provide a simple, scientific and reasonable method for water environment forewarning of lakes(reservoirs), the evaluations of water quality and forewarning level of Putian Dongzhen Reservoir, Fuqing Dongzhang Reservoir, and Sanming Dongyaxi Reservoir in Fujian Province were conducted.[Methods] According to the Weber-Fechner's model, dissolved oxygen(DO), chemical oxygen demand(COD_Mn), total phosphorus(TP), inorganic nitrogen(NH₃-N), total nitrogen(TN) were taken as the evaluation indicators of water environment for reservoirs. The water quality and forewarning level were evaluated using comprehensive index k_i of water environment.[Results] The water quality warning levels of Putian Dongzhen Reservoir in the 1st and 2nd quarters of 2010, and the 3rd quarter of 2012 were evaluated as moderate or strong warning. In the 3rd quarter of 2013, it was mild warning. In the 1st quarter of 2012, it was moderate to strong for Fuqing Dongzhang Reservoir. For Sanming Dongyaxi Reservoir, the warning level were mild in the 4th quarter of 2010, 3rd quarter of 2011, 3rd quarter of 2012, 3rd and 4th quarters in 2013. Otherwise, the warning levels of the above reservoirs were moderate.[Conclusion] The organoleptic water environmental quality could be evaluated and reflected objectively by the Weber-Fechner's model, which was considered as an effective tool to assess the effect of water environment quality. The model has the advantages of simple calculation process, high evaluation precision and good application. It provided a new method for comprehensive evaluation of water quality warning level for lakes (reservoirs) and expanded its application.