The study aims to determine the evolution of salt intrusion in the Mekong Delta in Vietnam. Salt water appeared in the mouths of rivers many years ago, but its values in 2019-2020 are considered the highest in the history of observations and surpass the data of 2016 (the year with the highest salinity). In 2020, the phenomenon of salt invasion will strongly manifest itself in the Mekong Delta in Vietnam (in the lower reaches of the Mekong River), the penetration of salt water deep into the mainland and the marginal salinity of 4 (g/l) deeper than 5-25 km, depending on the range. The main reason for this is the change in the flow of water from the headwaters. During the dry season, the flow in the estuary is completely dependent on the flow of water from the upper Mekong River, and the construction of hydroelectric power plants affects the water content of the river below the dams. The second reason is the inefficient operation of the fresh water circulation system between rivers during the dry season in Vietnam. Some other causes are related to climate change, such as rising sea levels at high tide, which allows salt water to flow inland from the mouth, as well as a rather wide shape of the mouth and deep penetration into the land, which contributes to faster penetration. All this negatively affects the environment and sustainable economic development of the Mekong Delta in Viet Nam. /Исследование направлено на определение эволюции солевой интрузии в дельте Меконга во Вьетнаме.