There is multicorrelation among the factors which affect the city water consumption. The result obtained by thetraditional least sequare method has a greater error than the true value. The partial leastsquare regression (PLS) is applied to set up the urban water use model based on the main component analysis and typical correlation analysis, it can solve the problem of interactive correlation among the independent variables and explain the dependent variables very well. The GM(1,1) model which is adopted to build the urban water consumption can overcome the obstruction of nonelinear parameters. The results and the practical data coincide very well in the midlong forecast. The coupling of the PLS and GM(1,1) model can obtain a good result which is more reaso
nable and reliable.