The procedures of maximumlikelihood,moments and least square method are used to estimate the parameters of Gumbel distribution.The statistical behaviors of these three estimate procedures are compared in theory and also in MonteCarlo simulation. Based on the data records at three survey stations of river A,the parameters estimates are given out by use of the three estimate procedures mentioned above respectively.It is concluded that maximumlikelihood method performs better and is more stable than the others.The curves of the highest water level in several years at the three survey stations of river A are presented at the end.