Salinity is a kind of soil including too much salt. It is a major factor affecting plant which leads to agricultural problem around the world. In the present, the problem is increasing its seriousness. The crops grown in salinity would obtain three types of plant salt stress as: 1) Osmotic stress caused by salt in the soil which would make the water potential to be decreased in lower level than normal. Consequently, the plant would have more difficulty in sucking the water, 2) Stress from accumulation of toxic ion, and 3) Stress caused by  construction and accumulation of anti-oxidants against the free radical substance. Therefore, when the plant received salt, it would have mechanism in preventing the cell from receiving danger from stress condition in the lowest level, for instance, the Na+ salt would be dismissed from cytoplasm to be stored in vacuole for keeping the ion balance, or  constructing more free radical substance or compatible solute substance, to be accumulated in the cell for keeping the water balance. The study of plant mechanism in salt stress would be guidelines for conducting research study in developing the plant species to be endure with Salt Stress situation. As a result, both of quantity, and quality of product would be increased especially in major economic plants of global people.