The aim of applying water stresses are two fold: a) to enhance Water Use Efficiency (WUE) and, b) to reach optimum-agronomic objectives (including, enhancing certain qualitative parameters of the crop, preventing excessive growth of aerial shoots of crops like sugar beet, etc.). This study was performed to evaluate the effect of irrigation interrupting time and its influence on the quality and quantity of sugar beet. The experimental design used Completely Randomized Blocks (CRB) methodology with 5 treatments; one to five weeks irrigation interruption before harvesting. Each treatment was planted on 5 lines with a 7 m length. The row spacing was 60 cm and the plants were 20 cm apart. The results of simple and combined analysis of variance in two years for different traits (root yield, impure sugar yield and white sugar yield, sugar content) showed that there is no significant impact by varying the parameters within the 5% statistical variance. Also, results of mean comparison for white sugar yield in the combined analysis proved that the greatest yield belonged to the 4th and 5th treatments with 9.11 and 9.12 ton/ha, respectively. Therefore, there is no significant difference regarding characteristics studied in statistical group, though even in some cases water stress can improve quality and increase sugar content percentage. So, irrigation interruption 4-5 weeks before harvesting in October can be suggested.