The water quality of lakes in Hanoi has been declining. In that, eutrophycation is the most popular. One of the effective tools for its accessing and predicting is the use of mathematical models. This paper used the Vollenweider model, Empirical watershed model and Jorgensen model to determine the eutrophycation of West Lake by Phosphorous concentration in the lake water. The results given by the models show that the ability of Eutrophication of West Lake is very high, because the content of Phosphorous in the lake exceed allowable value of standard () many times. The results of Jorgensen model are:.
