Abstract: According to the concept of Gini coefficient(GC),an index for estimating equity of the income,a method for evaluating fairness of water use is established. This method is used to assess the water use in Guangdong province in 2005,and the factors which are correlated to the allocation of water use are analyzed using the GC. The Lorenz curves of each factor are drawn,and the Gini coefficients are also calculated and analyzed. At last,the trend of the GC of each factor from 2000 to 2005 is given. The results show that the Lorenz curves and the GC of each factor can indicate the fairness of water use and also be helpful for water demand prediction and allocation.