The study has developed a set of criteria for assessing saltwater intrusion risk at commune level for Tien Giang province, a region with a relatively well-developed irrigation system, in three periods including present, 2030s and 2050s. The criteria for occurrence time of saltwater intrusion event have been added to show the impact of saltwater intrusion on agricultural production. The results show that the level of risk tends to increase from East to West, and the area at a very high level of risk gradually expands to the East over time. By 2050s, all communes in Tien Giang province show moderate to very high levels of risk due to saltwater intrusion. The study shows the influence of the irrigation system in reflecting the severity of saltwater intrusion in the area, through the opening/closing time of sluice gates, regulation systems of fresh water and the water storing capacity for production during saltwater intrusion event.