The goal of this study is to increase the tuber yield of potato cultivars by using of nutrient solution of sulfonated silicon with S8 sulfur element and to choose the most suitable method of using the nutrient solution under water deficit stress and normal conditions. This study was performed based on a split factorial experimental design in three replications in Ardabil Potato Research Station, IRAN in 2022. The main factor includes three levels of irrigation (100, 75, and 50% of plant usable water); the second factor includes foliar spraying with a nutrient solution in four stages of plant growth [(1) Tuber formation; (2) Tuber bulking; (3) Tuber formation and tuber bulking; (4) Control (Without nutritional solution)] and the third factor included three potato varieties (Agria, Rona and Takta). A nutrient solution of Sulfonated silicon with S8sulfur element was used for 5 liters per thousand of water. During the growth period, plant height, main stem number per plant, tuber number and weight per plant, tuber yield and water use efficiency were measured. The results showed that foliar spraying with a nutrient solution of sulfonated silicon with S-8 sulfur element amount 5 liters per thousand of water in the stages of tuber formation and tuber bulking increased tuber yield and water use efficiency under normal conditions (100% of plant usable water) about 14.24 ton per hectare and 2.44 kg/m3, under mild stress condition (75% of plant usable water) about 7.04 ton per hectare and 1.61 kg/m3 and under severe stress condition (50% of plant usable water) about 5.50 ton per hectare and 1.89 kg/m3, respectively. The use of the nutrient solution of sulfonated silicon with S8 sulfur element amount 5liters per thousand of water in the stages of tuber formation and tuber bulking increased tuber yield and its components and water use efficiency under normal, mild and severe conditions.